The energy spectrum of the hydrogen atom has been applied in calculating the time rate of energy transitions between the quantum states of the atom. The formal basis of the approach has been provided by the quantum pr...The energy spectrum of the hydrogen atom has been applied in calculating the time rate of energy transitions between the quantum states of the atom. The formal basis of the approach has been provided by the quantum properties of energy and time deduced from the Joule-Lenz law. The rates of the energy transitions obtained in this way were compared with the quantum-mechanical probabilities of transitions calculated earlier by Bethe and Condon and Shortley for the same pairs of the quantum states.展开更多
We propose a quantum-mechanical Brayton engine model that works between two superposed states,employing a single particle confined in an arbitrary power-law trap as the working substance. Applying the superposition pr...We propose a quantum-mechanical Brayton engine model that works between two superposed states,employing a single particle confined in an arbitrary power-law trap as the working substance. Applying the superposition principle,we obtain the explicit expressions of the power and efficiency,and find that the efficiency at maximum power is bounded from above by the function: η+= θ/(θ+1),with θ being a potential-dependent exponent.展开更多
The performance in finite time of a quantum-mechanical Brayton engine cycle is discussed, without intro- duction of temperature. The engine model consists of two quantum isoenergetic and two quantum isobaric processes...The performance in finite time of a quantum-mechanical Brayton engine cycle is discussed, without intro- duction of temperature. The engine model consists of two quantum isoenergetic and two quantum isobaric processes, and works with a single particle in a harmonic trap. Directly employing the finite-time thermodynamics, the efficiency at maximum power output is determined. Extending the harmonic trap to a power-law trap, we find that the efficiency at max/mum power is independent of any parameter involved in the model, but depends on the confinement of the trapping potential.展开更多
The paper applies a one-to-one correspondence which exists between individual Schr?dinger perturbation terms and the diagrams obtained on a circular scale of time to whole sets of the Schr?dinger terms belonging to a ...The paper applies a one-to-one correspondence which exists between individual Schr?dinger perturbation terms and the diagrams obtained on a circular scale of time to whole sets of the Schr?dinger terms belonging to a definite perturbation order. In effect the diagram properties allowed us to derive the recurrence formulae giving the number of higher perturbative terms from the number of lower order terms. This recurrence formalism is based on a complementary property that any perturbation order N can be composed of two positive integer components Na , Nb combined into N in all possible ways. Another result concerns the degeneracy of the perturbative terms. This degeneracy is shown to be only twofold and the terms having it are easily detectable on the basis of a circular scale. An analysis of this type demonstrates that the degeneracy of the perturbative terms does not exist for very low perturbative orders. But when the perturbative order exceeds five, the number of degenerate terms predominates heavily over that of nondegenerate terms.展开更多
The Schrodinger perturbation energy for an arbitrary order N of the perturbation has been presented with the aid of a circular scale of time. The method is of a recurrent character and developed for a non-degenerate q...The Schrodinger perturbation energy for an arbitrary order N of the perturbation has been presented with the aid of a circular scale of time. The method is of a recurrent character and developed for a non-degenerate quantum state. It allows one to reduce the inflation of terms necessary to calculate known from the Feynman’s diagrammatical approach to a number below that applied in the original Schrodinger perturbation theory.展开更多
In order to apply the recently published planar atom model of Helium with well-defined electron trajectories onto the results about the thermal radiative behaviour of gases,which was published by the author in 2016,th...In order to apply the recently published planar atom model of Helium with well-defined electron trajectories onto the results about the thermal radiative behaviour of gases,which was published by the author in 2016,the latter publication had to be partly questioned since its theoretical evaluation contains several errors.Nevertheless,the basic statements made therein,applying the kinetic gas theory,are still valid.Since they cannot be assumed as commonly known,first,the description of the measurement equipment and the applied light sources,the most relevant results,and the basic theoretical interpretation were recapitulated.The essential empirical result of those measurements was the observation that any gas is warmed up when it is thermally irradiated,but solely up to a limiting temperature where the absorption intensity of the gas is equal to its emission intensity.This effect was first observed in air and in CO_(2),whereby the limiting temperatures were nearly equal.But it also occurred in the noble gases Argon,Neon and Helium,whereby the limiting temperatures depended on the type of gas.These differences could be explained by means of the kinetic gas theory,assuming proportionality between the collision wattage of the atoms and the radiation wattage.As a consequence,an additional energy must exist,which does not appear in the classic thermodynamic theory,and which must be due to an oscillating process at the electrons.In order to explain this,using the example of Helium,the said atom model is adduced.Since it exhibits well-defined electron trajectories—in contrast to the orthodox orbital model where the electrons underlie probabilities of presence—such an oscillation process,implicating an excited state of the electrons,is well describable.Thereto,a modified harmonic oscillator comes into question.This oscillator is eccentric since it rotates around the nucleus.Moreover,it is asymmetric since its energetic conditions are asymmetric with respect to the orbit path.In particular,the quantum-mechanical condition of a standing wave must be fulfilled,i.e.the angular velocityωosc of the oscillator must be an integer multiple of the angular rotation velocityωrot,preferably 2.By equating the oscillation energy of the electrons and the radiation energy,which is determined by Einstein’s equation for the photoelectric effect,and by applying the theorem of conservation of momentum P onto the collision process,thermodynamics could be bridged with quantum mechanics,delivering in the excited state an elliptic orbit.The essential difference between the orthodox and the alternative model consists in the fact that the orthodox model only considers the observers’point of view,whereas the alternative model distinguishes between object and observer.Thereby,the isolated model is two-dimensional,obeying the here described quantum mechanical computation,whereas from the viewpoint of the observer,it is three-dimensional,due to the thermally induced rotation.展开更多
We investigate the quantum-mechanical effects on the electrical properties of the double-gate j unction- less field effect transistors. The quantum-mechanical effect, or carrier energy-quantization effects on the thre...We investigate the quantum-mechanical effects on the electrical properties of the double-gate j unction- less field effect transistors. The quantum-mechanical effect, or carrier energy-quantization effects on the threshold voltage, of DG-JLFET are analytically modeled and incorporated in the Duarte et al. model and then verified by TCAD simulation.展开更多
Quantum aspects of the Joule-Lenz law for the transmission of energy allowed us to calculate the time rate of energy transitions between the quantum states of the hydrogen atom in a fully non-probabilistic way. The ca...Quantum aspects of the Joule-Lenz law for the transmission of energy allowed us to calculate the time rate of energy transitions between the quantum states of the hydrogen atom in a fully non-probabilistic way. The calculation has been extended to all transitions between p and s states having main quantum numbers not exceeding 6. An evident similarity between the intensity pattern obtained from the Joule-Lenz law and the corresponding quantum-mechanical transition pro-babilities has been shown.展开更多
The purpose of this study was to develop a physico-mathematical model and technique for estimation of chemical bond stability depending on electric field intensity of an external point charge.A hypothesis for a possib...The purpose of this study was to develop a physico-mathematical model and technique for estimation of chemical bond stability depending on electric field intensity of an external point charge.A hypothesis for a possible physico-chemical mechanism of the formation of additional harmful gases in the rock destruction by blasting was proposed.The theoretical basis of the hypothesis is the method of theretical evaluation of bond energy depending on the distance to a point charge,the third Coulomb centre.The quantum-mechanical model for calculating the electronic terms of molecules makes it possible to solve problems associated with the determination of parameters of molecules under the action of various physical fields on the system under consideration.The model was approved for some diatomic molecules.The discrepancy between the experimental data and calculated data did not exceed 14%,which proves accuracy of the obtained results.The model can be used in the field of research into the causes of gas-dynamic phenomena in underground coal mines,in studies of the degree of stability of nanostructured components of coal under physical influences,and in the theoretical design of new compounds and structures in the field of nanomaterial science and nanotechnology.展开更多
A monocyclopentadienyl titanium complex containing 8-quinolinolato (QCpTiCl_2) was synthesized. Its activities in ethylene polymerization at various Al/Ti molar ratios, different temperatures and activation time were ...A monocyclopentadienyl titanium complex containing 8-quinolinolato (QCpTiCl_2) was synthesized. Its activities in ethylene polymerization at various Al/Ti molar ratios, different temperatures and activation time were investigated. The activity with a Al/Ti molar ratio of 500 exhibited a maximum of 2.8×10~5 g/(mol.h) at 30℃. The activation time of QCpTiCl_2 with MAO before polymerization also plays a role on the activity. The structural properties of the produced polyethylene (molecular weight, molecular weight distribution and melting point) were discussed. Kinetic behaviors of ethylene polymerization with the QCpTiCl_2/MAO system at different Al/Ti molar ratios were studied. For the QCpTiMeCl/MAO system and the CpTiMe_2Cl/MAO system, binding energies of the examined intermediates were calculated by quantum-mechanical method based on ADF program, respectively. It is confirmed that the chlorinebridged adduct formed by the reaction of QCpTiMeCl with MAO is thermodynamically steady. In the case of the QCpTiMeCl/MAO system, olefin-separated ion pair (OSIP) mechanism is much favorable than ion-pair dissociation (IPD) mechanism. The experimental result on the CpTiMe_2Cl/MAO system showed lower activity for ethylene polymerization than that on the QCpTiMeCl/MAO system, which revealed that the CpTiMe_2Cl/MAO system is unfavorable to form active species with ethylene.展开更多
The low-energy mutual neutralization(MN)reactions Na^(+)+H^(-)→Na(nl)+H have been studied by employing the full quantum-mechanical molecular-orbital close-coupling(QMOCC)method over a wide energy range of 10^(-3)-10^...The low-energy mutual neutralization(MN)reactions Na^(+)+H^(-)→Na(nl)+H have been studied by employing the full quantum-mechanical molecular-orbital close-coupling(QMOCC)method over a wide energy range of 10^(-3)-10^(3) e V/u.Total and state-selective cross sections have been investigated and compared with the available theoretical and experimental data,and the state-selective rate coefficients for the temperature range of 100-10000 K have been obtained.In the present work,all the necessary highly excited states are included,and the influences of rotational couplings and 10 active electrons are considered.It is found that in the energy below 10 e V/u,the Na(4s)state is the most dominant exit state with a contribution of approximately 78%to the branch fraction,which is in best agreement with the experimental data.For energies above 10 e V/u,the MN total cross section is larger than those obtained in other theoretical calculations and shows a slow decreasing trend because the main exit states change,when the energy is above 100 e V/u,the dominant exit state becomes the Na(3p)state,while the Na(4s)state becomes the third most important exit state.The datasets presented in this paper,including the potential energy curve,the radial and rotational couplings,the total and state-selective cross sections,are openly available at https://doi.org/10.57760/sciencedb.j00113.00112.展开更多
The electron excitation processes of H(1s)+He(1s^(2))→H(2s/2p)+He(1s^(2))are studied in impact energy range of 20-2000 e V/u by using the quantum-mechanical molecular orbital close-coupling(QMOCC)method.Total and sta...The electron excitation processes of H(1s)+He(1s^(2))→H(2s/2p)+He(1s^(2))are studied in impact energy range of 20-2000 e V/u by using the quantum-mechanical molecular orbital close-coupling(QMOCC)method.Total and state-selective cross sections have been obtained and compared with the available theoretical and experimental results.The results agree well with available measurements in the overlapping energy regions overall.The comparison of our results with other theoretical calculations further demonstrates the importance of considering a sufficient number of channels.The datasets presented in this paper,including the excitation cross sections,are openly available at https://www.doi.org/10.57760/sciencedb.j00113.00083.展开更多
We investigate the entanglement in the interacting system of a single mode thermal field and a single qubit with dissipation in the dispersive limit. The influence of initial temperature of thermal field and atoms on ...We investigate the entanglement in the interacting system of a single mode thermal field and a single qubit with dissipation in the dispersive limit. The influence of initial temperature of thermal field and atoms on the entanglement is then examined.展开更多
We investigate several Hamiltonians for a free particle in a one-dimensional box, in the context of supersymmetric quantum mechanics. Specifically, we study this problem with the Neumann boundary condition, the period...We investigate several Hamiltonians for a free particle in a one-dimensional box, in the context of supersymmetric quantum mechanics. Specifically, we study this problem with the Neumann boundary condition, the periodic and antiperiodic boundary condition, and some mixed and complex boundary conditions. This is achieved by using an approach recently proposed which expresses the factorization of the partner Hamiltonians in terms of the probability density and current for the ground-state eigenfunction of one of them.展开更多
A Fock-Darwin system in noncommutative quantum mechanics is studied. By constructing Heisenberg algebra we obtain the levels on noncommutative space and noncommutative phase space, and give the corrections to the resu...A Fock-Darwin system in noncommutative quantum mechanics is studied. By constructing Heisenberg algebra we obtain the levels on noncommutative space and noncommutative phase space, and give the corrections to the results in usual quantum mechanics. Moreover, to search the difference among the three spaces, the degeneracy is analysed by two ways, the value of ω/ωe and certain algebra realization （SU（2）and SU（1,1））, and some interesting properties in the magnetic field limit are exhibited, such as totally different degeneracy and magic number distribution for the given frequency or mass of a system in strong magnetic field.展开更多
The original intention of the author’s preoccupation with the quantum-me-chanical behaviour of simple atoms and molecules such as Hydrogen and He-lium was,on the one hand,the elegant simplicity of Niels Bohr’s atom ...The original intention of the author’s preoccupation with the quantum-me-chanical behaviour of simple atoms and molecules such as Hydrogen and He-lium was,on the one hand,the elegant simplicity of Niels Bohr’s atom model for Hydrogen,describing the metastable states of the excited electrons by pla-nar concentric electron orbits,and,on the other hand,the hardly intelligible wave mechanical approach of Heisenberg,Schrödinger and others,describing mainly atoms with multiple electrons by three-dimensional orbitals which were characterized by probabilities of presence.Thereby the question arose whether it would be possible to find alternative atom models with well-defined electron trajectories.Therein,Louis de Broglie’s thesis of the wavy nature of electron motion implicating standing waves would have to be implemented.Nevertheless,as reviewed in the introduction,the orthodox three-dimensional concept influenced the own thinking in such a way that three-dimensional constellations for the electronic excited states were conceived.The break-through was achieved for the electronic ground state in the form of the spin-orbit coupling where the spin acts as a perpetuum mobile,inducing the orbital angular momentum h/2π.Furthermore,the insight was gained that a circu-larly rotating electron intrinsically corresponds to a harmonic oscillator,thus fulfilling the condition of a standing wave.Based on this concept,a double planar model was established for the H2-molecule which could be empirically verified by X-ray data from literature.However,for the two electrons contain-ing Helium a 2D-array seemed impossible since the Pauli-principle seemed to be violated.After a long stepwise succession of 3D-attempts which turned out to be impossible—not least since eccentric forces are not possible in such a system—the here presented 2D-version for Helium was found,composed by two imaginary orthogonal electron orbits.It will enable in a subsequent pub-lication the quantum mechanical interpretation of the thermal-radiative be-haviour of Helium which was reported in the author’s publication nine years ago.展开更多
DNA autoionization is a fundamental process wherein ultraviolet （UV）- photoexcited nucleobases dissipate energy by charge transfer to the environment without undergoing chemical damage. Here, single-wall carbon nano...DNA autoionization is a fundamental process wherein ultraviolet （UV）- photoexcited nucleobases dissipate energy by charge transfer to the environment without undergoing chemical damage. Here, single-wall carbon nanotubes （SWNT） are explored as a photoluminescent reporter for the study of the mechanism and rates of DNA autoionization. Two-color photoluminescence spectroscopy allows separate photoexcitation of the DNA and the SWNTs in the UV and visible range, respectively. A strong SWNT photoluminescence quenching is observed when the UV pump is resonant with the DNA absorption, consistent with charge transfer from the excited states of the DNA to the SWNT. Semiempirical calculations of the DNA-SWNT electronic structure, combined with a Green＇s function theory for charge transfer, show a 20 fs autoionization rate, dominated by hole transfer. Rate-equation analysis of the spectroscopy data confirms that the quenching rate is limited by thermalization of the free charge carriers transferred to the nanotube reservoir. This approach has great potential for monitoring DNA excitation, autoionization, and chemical damage, both in vivo and in vitro.展开更多
Symmetry can dramatically reduce the computational cost （running time and memory allocation） of Self-Consistent-Field ab initio calculations for crystalline systems. Crucial for running time is use of symmetry in th...Symmetry can dramatically reduce the computational cost （running time and memory allocation） of Self-Consistent-Field ab initio calculations for crystalline systems. Crucial for running time is use of symmetry in the evaluation of one- and two-electron integrals, diagonalization of the Fock matrix at selected points in reciprocal space, reconstruction of the density matrix. As regards memory allocation, full square matrices （overlap, Fock and density） in the Atomic Orbital （AO） basis are avoided and a direct transformation from the packed AO to the SACO （Symmetry Adapted Crystalline Orbital） basis is per- formed, so that the largest matrix to be handled has the size of the largest sub-block in the latter basis. We here illustrate the effectiveness of this scheme, following recent advancements in the CRYSTAL code, concerning memory allocation and direct basis set transformation. Quantitative examples are given for large unit cell systems, such as zeolites （all-silica faujasite and silicalite MF1） and garnets （pyrope）. It is shown that the full SCF of 3D systems containing up to 576 atoms and 11136 Atomic Orbitals in the cell can be run with a hybrid functional on a single core PC with 500 MB RAM in about 8 h.展开更多
文摘The energy spectrum of the hydrogen atom has been applied in calculating the time rate of energy transitions between the quantum states of the atom. The formal basis of the approach has been provided by the quantum properties of energy and time deduced from the Joule-Lenz law. The rates of the energy transitions obtained in this way were compared with the quantum-mechanical probabilities of transitions calculated earlier by Bethe and Condon and Shortley for the same pairs of the quantum states.
基金Supported by the National Natural Science Foundation of China under Grant Nos.1150509111265010+1 种基金and 11365015the Jiangxi Provincial Natural Science Foundation under Grant No.20132BAB212009
文摘We propose a quantum-mechanical Brayton engine model that works between two superposed states,employing a single particle confined in an arbitrary power-law trap as the working substance. Applying the superposition principle,we obtain the explicit expressions of the power and efficiency,and find that the efficiency at maximum power is bounded from above by the function: η+= θ/(θ+1),with θ being a potential-dependent exponent.
基金Supported by the National Natural Science Foundation of China under Grant No. 11265010, the Jiangxi Provincial Natural Science Foundation under Grant No. 20132BAB212009, University Young Teacher Training Program of the SMEC under Grant No. egdll005, and by Innovation Program of the SMEC under Grant No. 12YZ177
文摘The performance in finite time of a quantum-mechanical Brayton engine cycle is discussed, without intro- duction of temperature. The engine model consists of two quantum isoenergetic and two quantum isobaric processes, and works with a single particle in a harmonic trap. Directly employing the finite-time thermodynamics, the efficiency at maximum power output is determined. Extending the harmonic trap to a power-law trap, we find that the efficiency at max/mum power is independent of any parameter involved in the model, but depends on the confinement of the trapping potential.
文摘The paper applies a one-to-one correspondence which exists between individual Schr?dinger perturbation terms and the diagrams obtained on a circular scale of time to whole sets of the Schr?dinger terms belonging to a definite perturbation order. In effect the diagram properties allowed us to derive the recurrence formulae giving the number of higher perturbative terms from the number of lower order terms. This recurrence formalism is based on a complementary property that any perturbation order N can be composed of two positive integer components Na , Nb combined into N in all possible ways. Another result concerns the degeneracy of the perturbative terms. This degeneracy is shown to be only twofold and the terms having it are easily detectable on the basis of a circular scale. An analysis of this type demonstrates that the degeneracy of the perturbative terms does not exist for very low perturbative orders. But when the perturbative order exceeds five, the number of degenerate terms predominates heavily over that of nondegenerate terms.
文摘The Schrodinger perturbation energy for an arbitrary order N of the perturbation has been presented with the aid of a circular scale of time. The method is of a recurrent character and developed for a non-degenerate quantum state. It allows one to reduce the inflation of terms necessary to calculate known from the Feynman’s diagrammatical approach to a number below that applied in the original Schrodinger perturbation theory.
文摘In order to apply the recently published planar atom model of Helium with well-defined electron trajectories onto the results about the thermal radiative behaviour of gases,which was published by the author in 2016,the latter publication had to be partly questioned since its theoretical evaluation contains several errors.Nevertheless,the basic statements made therein,applying the kinetic gas theory,are still valid.Since they cannot be assumed as commonly known,first,the description of the measurement equipment and the applied light sources,the most relevant results,and the basic theoretical interpretation were recapitulated.The essential empirical result of those measurements was the observation that any gas is warmed up when it is thermally irradiated,but solely up to a limiting temperature where the absorption intensity of the gas is equal to its emission intensity.This effect was first observed in air and in CO_(2),whereby the limiting temperatures were nearly equal.But it also occurred in the noble gases Argon,Neon and Helium,whereby the limiting temperatures depended on the type of gas.These differences could be explained by means of the kinetic gas theory,assuming proportionality between the collision wattage of the atoms and the radiation wattage.As a consequence,an additional energy must exist,which does not appear in the classic thermodynamic theory,and which must be due to an oscillating process at the electrons.In order to explain this,using the example of Helium,the said atom model is adduced.Since it exhibits well-defined electron trajectories—in contrast to the orthodox orbital model where the electrons underlie probabilities of presence—such an oscillation process,implicating an excited state of the electrons,is well describable.Thereto,a modified harmonic oscillator comes into question.This oscillator is eccentric since it rotates around the nucleus.Moreover,it is asymmetric since its energetic conditions are asymmetric with respect to the orbit path.In particular,the quantum-mechanical condition of a standing wave must be fulfilled,i.e.the angular velocityωosc of the oscillator must be an integer multiple of the angular rotation velocityωrot,preferably 2.By equating the oscillation energy of the electrons and the radiation energy,which is determined by Einstein’s equation for the photoelectric effect,and by applying the theorem of conservation of momentum P onto the collision process,thermodynamics could be bridged with quantum mechanics,delivering in the excited state an elliptic orbit.The essential difference between the orthodox and the alternative model consists in the fact that the orthodox model only considers the observers’point of view,whereas the alternative model distinguishes between object and observer.Thereby,the isolated model is two-dimensional,obeying the here described quantum mechanical computation,whereas from the viewpoint of the observer,it is three-dimensional,due to the thermally induced rotation.
文摘We investigate the quantum-mechanical effects on the electrical properties of the double-gate j unction- less field effect transistors. The quantum-mechanical effect, or carrier energy-quantization effects on the threshold voltage, of DG-JLFET are analytically modeled and incorporated in the Duarte et al. model and then verified by TCAD simulation.
文摘Quantum aspects of the Joule-Lenz law for the transmission of energy allowed us to calculate the time rate of energy transitions between the quantum states of the hydrogen atom in a fully non-probabilistic way. The calculation has been extended to all transitions between p and s states having main quantum numbers not exceeding 6. An evident similarity between the intensity pattern obtained from the Joule-Lenz law and the corresponding quantum-mechanical transition pro-babilities has been shown.
基金The studies were accomplished within the framework of the project"Investigation of coal nanostructure as a source of coal mine methane"with a financial support of the Ministry of Education and Science of Ukraine according to the Order No.199 of February 10,2017.
文摘The purpose of this study was to develop a physico-mathematical model and technique for estimation of chemical bond stability depending on electric field intensity of an external point charge.A hypothesis for a possible physico-chemical mechanism of the formation of additional harmful gases in the rock destruction by blasting was proposed.The theoretical basis of the hypothesis is the method of theretical evaluation of bond energy depending on the distance to a point charge,the third Coulomb centre.The quantum-mechanical model for calculating the electronic terms of molecules makes it possible to solve problems associated with the determination of parameters of molecules under the action of various physical fields on the system under consideration.The model was approved for some diatomic molecules.The discrepancy between the experimental data and calculated data did not exceed 14%,which proves accuracy of the obtained results.The model can be used in the field of research into the causes of gas-dynamic phenomena in underground coal mines,in studies of the degree of stability of nanostructured components of coal under physical influences,and in the theoretical design of new compounds and structures in the field of nanomaterial science and nanotechnology.
基金The work is sub sidized by Special Funds for Major State Basis Research Projects of China(No.G1999064801)
文摘A monocyclopentadienyl titanium complex containing 8-quinolinolato (QCpTiCl_2) was synthesized. Its activities in ethylene polymerization at various Al/Ti molar ratios, different temperatures and activation time were investigated. The activity with a Al/Ti molar ratio of 500 exhibited a maximum of 2.8×10~5 g/(mol.h) at 30℃. The activation time of QCpTiCl_2 with MAO before polymerization also plays a role on the activity. The structural properties of the produced polyethylene (molecular weight, molecular weight distribution and melting point) were discussed. Kinetic behaviors of ethylene polymerization with the QCpTiCl_2/MAO system at different Al/Ti molar ratios were studied. For the QCpTiMeCl/MAO system and the CpTiMe_2Cl/MAO system, binding energies of the examined intermediates were calculated by quantum-mechanical method based on ADF program, respectively. It is confirmed that the chlorinebridged adduct formed by the reaction of QCpTiMeCl with MAO is thermodynamically steady. In the case of the QCpTiMeCl/MAO system, olefin-separated ion pair (OSIP) mechanism is much favorable than ion-pair dissociation (IPD) mechanism. The experimental result on the CpTiMe_2Cl/MAO system showed lower activity for ethylene polymerization than that on the QCpTiMeCl/MAO system, which revealed that the CpTiMe_2Cl/MAO system is unfavorable to form active species with ethylene.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12204288,11934004,and 12203106)。
文摘The low-energy mutual neutralization(MN)reactions Na^(+)+H^(-)→Na(nl)+H have been studied by employing the full quantum-mechanical molecular-orbital close-coupling(QMOCC)method over a wide energy range of 10^(-3)-10^(3) e V/u.Total and state-selective cross sections have been investigated and compared with the available theoretical and experimental data,and the state-selective rate coefficients for the temperature range of 100-10000 K have been obtained.In the present work,all the necessary highly excited states are included,and the influences of rotational couplings and 10 active electrons are considered.It is found that in the energy below 10 e V/u,the Na(4s)state is the most dominant exit state with a contribution of approximately 78%to the branch fraction,which is in best agreement with the experimental data.For energies above 10 e V/u,the MN total cross section is larger than those obtained in other theoretical calculations and shows a slow decreasing trend because the main exit states change,when the energy is above 100 e V/u,the dominant exit state becomes the Na(3p)state,while the Na(4s)state becomes the third most important exit state.The datasets presented in this paper,including the potential energy curve,the radial and rotational couplings,the total and state-selective cross sections,are openly available at https://doi.org/10.57760/sciencedb.j00113.00112.
基金supported by the National Natural Science Foundation of China(Grant Nos.12204288,11934004,and 12274040)
文摘The electron excitation processes of H(1s)+He(1s^(2))→H(2s/2p)+He(1s^(2))are studied in impact energy range of 20-2000 e V/u by using the quantum-mechanical molecular orbital close-coupling(QMOCC)method.Total and state-selective cross sections have been obtained and compared with the available theoretical and experimental results.The results agree well with available measurements in the overlapping energy regions overall.The comparison of our results with other theoretical calculations further demonstrates the importance of considering a sufficient number of channels.The datasets presented in this paper,including the excitation cross sections,are openly available at https://www.doi.org/10.57760/sciencedb.j00113.00083.
文摘We investigate the entanglement in the interacting system of a single mode thermal field and a single qubit with dissipation in the dispersive limit. The influence of initial temperature of thermal field and atoms on the entanglement is then examined.
文摘We investigate several Hamiltonians for a free particle in a one-dimensional box, in the context of supersymmetric quantum mechanics. Specifically, we study this problem with the Neumann boundary condition, the periodic and antiperiodic boundary condition, and some mixed and complex boundary conditions. This is achieved by using an approach recently proposed which expresses the factorization of the partner Hamiltonians in terms of the probability density and current for the ground-state eigenfunction of one of them.
基金Supported by the National Natural Science Foundation of China under Grant No 10575026, and the Natural Science Foundation of Zhejiang Provence under Grant No Y607437.
文摘A Fock-Darwin system in noncommutative quantum mechanics is studied. By constructing Heisenberg algebra we obtain the levels on noncommutative space and noncommutative phase space, and give the corrections to the results in usual quantum mechanics. Moreover, to search the difference among the three spaces, the degeneracy is analysed by two ways, the value of ω/ωe and certain algebra realization （SU（2）and SU（1,1））, and some interesting properties in the magnetic field limit are exhibited, such as totally different degeneracy and magic number distribution for the given frequency or mass of a system in strong magnetic field.
文摘The original intention of the author’s preoccupation with the quantum-me-chanical behaviour of simple atoms and molecules such as Hydrogen and He-lium was,on the one hand,the elegant simplicity of Niels Bohr’s atom model for Hydrogen,describing the metastable states of the excited electrons by pla-nar concentric electron orbits,and,on the other hand,the hardly intelligible wave mechanical approach of Heisenberg,Schrödinger and others,describing mainly atoms with multiple electrons by three-dimensional orbitals which were characterized by probabilities of presence.Thereby the question arose whether it would be possible to find alternative atom models with well-defined electron trajectories.Therein,Louis de Broglie’s thesis of the wavy nature of electron motion implicating standing waves would have to be implemented.Nevertheless,as reviewed in the introduction,the orthodox three-dimensional concept influenced the own thinking in such a way that three-dimensional constellations for the electronic excited states were conceived.The break-through was achieved for the electronic ground state in the form of the spin-orbit coupling where the spin acts as a perpetuum mobile,inducing the orbital angular momentum h/2π.Furthermore,the insight was gained that a circu-larly rotating electron intrinsically corresponds to a harmonic oscillator,thus fulfilling the condition of a standing wave.Based on this concept,a double planar model was established for the H2-molecule which could be empirically verified by X-ray data from literature.However,for the two electrons contain-ing Helium a 2D-array seemed impossible since the Pauli-principle seemed to be violated.After a long stepwise succession of 3D-attempts which turned out to be impossible—not least since eccentric forces are not possible in such a system—the here presented 2D-version for Helium was found,composed by two imaginary orthogonal electron orbits.It will enable in a subsequent pub-lication the quantum mechanical interpretation of the thermal-radiative be-haviour of Helium which was reported in the author’s publication nine years ago.
基金T. I. and S. V. R. acknowledge support by National Science Foundation （Nos. ECCS-1202398 and ECCS- 1509786） P. S. acknowledges REU NSF （No. PHY- 1359195）. A. B. acknowledges the startup fund support from the University of Central Florida. The authors gratefully acknowledge access to facilities at the National Institute of Standards and Technology for PL measurements and the computational time support from the UCF Advanced Research Computing Center STOKES. We are thankful to Dr. J. Fagan as the host at NIST, Dr. J. Reimers for providing us with the CNDO code, and Dr. D. Roxbury for providing the MD trajectory.
文摘DNA autoionization is a fundamental process wherein ultraviolet （UV）- photoexcited nucleobases dissipate energy by charge transfer to the environment without undergoing chemical damage. Here, single-wall carbon nanotubes （SWNT） are explored as a photoluminescent reporter for the study of the mechanism and rates of DNA autoionization. Two-color photoluminescence spectroscopy allows separate photoexcitation of the DNA and the SWNTs in the UV and visible range, respectively. A strong SWNT photoluminescence quenching is observed when the UV pump is resonant with the DNA absorption, consistent with charge transfer from the excited states of the DNA to the SWNT. Semiempirical calculations of the DNA-SWNT electronic structure, combined with a Green＇s function theory for charge transfer, show a 20 fs autoionization rate, dominated by hole transfer. Rate-equation analysis of the spectroscopy data confirms that the quenching rate is limited by thermalization of the free charge carriers transferred to the nanotube reservoir. This approach has great potential for monitoring DNA excitation, autoionization, and chemical damage, both in vivo and in vitro.
基金Compagnia di San Paolo for financial support(Progetti di Ricerca di Ateneo-Compagnia di San Paolo-2011-Linea 1A,progetto ORTO11RRT5)Claudio Zicovich-Wilson acknowledges financial support from Mexican CONACyT through project CB-178853
文摘Symmetry can dramatically reduce the computational cost （running time and memory allocation） of Self-Consistent-Field ab initio calculations for crystalline systems. Crucial for running time is use of symmetry in the evaluation of one- and two-electron integrals, diagonalization of the Fock matrix at selected points in reciprocal space, reconstruction of the density matrix. As regards memory allocation, full square matrices （overlap, Fock and density） in the Atomic Orbital （AO） basis are avoided and a direct transformation from the packed AO to the SACO （Symmetry Adapted Crystalline Orbital） basis is per- formed, so that the largest matrix to be handled has the size of the largest sub-block in the latter basis. We here illustrate the effectiveness of this scheme, following recent advancements in the CRYSTAL code, concerning memory allocation and direct basis set transformation. Quantitative examples are given for large unit cell systems, such as zeolites （all-silica faujasite and silicalite MF1） and garnets （pyrope）. It is shown that the full SCF of 3D systems containing up to 576 atoms and 11136 Atomic Orbitals in the cell can be run with a hybrid functional on a single core PC with 500 MB RAM in about 8 h.
