We give a detailed examination of potential energy curves of the singlet and triplet states of CFC1 correlated with the lowest three dissociation limits. The calculations are carried out at the internally contracted m...We give a detailed examination of potential energy curves of the singlet and triplet states of CFC1 correlated with the lowest three dissociation limits. The calculations are carried out at the internally contracted multi- reference configuration interaction/cc-pV（T＋d）Z level with the other two geometric parameters fixed at the state equilibrium conformation. The vertical transition energy, the oscillator strength, the main configuration and the electron transition are also investigated at the same level.展开更多
The Hartree-Fock equation is non-linear and has, in principle, multiple solutions. The ωth HF extreme and its associated virtual spin-orbitals furnish an orthogonal base Bω of the full configuration interaction spac...The Hartree-Fock equation is non-linear and has, in principle, multiple solutions. The ωth HF extreme and its associated virtual spin-orbitals furnish an orthogonal base Bω of the full configuration interaction space. Although all Bω bases generate the same CI space, the corresponding configurations of each Bω base have distinct quantum-mechanical information contents. In previous works, we have introduced a multi-reference configuration interaction method, based on the multiple extremes of the Hartree-Fock problem. This method was applied to calculate the permanent electrical dipole and quadrupole moments of some small molecules using minimal and double, triple and polarized double-zeta bases. In all cases were possible, using a reduced number of configurations, to obtain dipole and quadrupole moments in close agreement with the experimental values and energies without compromising the energy of the state function. These results show the positive effect of the use of the multi-reference Hartree-Fock bases that allowed a better extraction of quantum mechanical information from the several Bω bases. But to extend these ideas for larger systems and atomic bases, it is necessary to develop criteria to build the multireference Hartree-Fock bases. In this project, we are beginning a study of the non-uniform distribution of quantum-mechanical information content of the Bω bases, searching identify the factors that allowed obtain the good results cited展开更多
The potential energy curves（PECs） of the first electronic excited state of S2（a^1△g） are calculated employing a multi-reference configuration interaction method with the Davidson correction in combination with a ...The potential energy curves（PECs） of the first electronic excited state of S2（a^1△g） are calculated employing a multi-reference configuration interaction method with the Davidson correction in combination with a series of correlationconsistent basis sets from Dunning： aug-cc-p VX Z（X = T, Q, 5, 6）. In order to obtain PECs with high accuracy, PECs calculated with aug-cc-p V（Q, 5）Z basis sets are extrapolated to the complete basis set limit. The resulting PECs are then fitted to the analytical potential energy function（APEF） using the extended Hartree–Fock approximate correlation energy method. By utilizing the fitted APEF, accurate and reliable spectroscopic parameters are obtained, which are consistent with both experimental and theoretical results. By solving the Schr o¨dinger equation numerically with the APEFs obtained at the AV6 Z and the extrapolated AV（Q, 5）Z level of theory, we calculate the complete set of vibrational levels, classical turning points, inertial rotation and centrifugal distortion constants.展开更多
A globally accurate potential energy surface is reported for the electronic ground-state H2O＋. The ab initio energies utilized to map the potential energy surface are calculated at the multireference configuration in...A globally accurate potential energy surface is reported for the electronic ground-state H2O＋. The ab initio energies utilized to map the potential energy surface are calculated at the multireference configuration interaction method employing the aug-cc-pVQZ basis set and the full valence complete active space wave function as reference. In order to improve accu- racy of the resulting raw ab initio energies, they are then extrapolated to the complete basis set limit and most importantly to the full configuration-interaction limit by semiempirically correcting the dynamical correlation using the double many- body expansion-scaled external correlation method. The topographical features of the current potential energy surface were examined in detail, which agree nicely with those of other theoretical work.展开更多
The potential energy curves （PECs） of X2∑ and A2П states of the CN molecule have been calculated with the multi- reference configuration interaction method and the aug-cc-pwCVSZ basis set. Based on the PECs, all o...The potential energy curves （PECs） of X2∑ and A2П states of the CN molecule have been calculated with the multi- reference configuration interaction method and the aug-cc-pwCVSZ basis set. Based on the PECs, all of the vibrational and rotational levels of the 13C14N molecule are obtained by solving the Schrrdinger equation of the molecular nuclear motion. The spectroscopic parameters are determined by fitting the Dunham coefficients with the levels. Both the levels and the spectroscopic parameters are in good qualitative agreement with the experimental data available. The analytical potential energy functions are also deduced from the calculated PECs. The present results can provide a helpful reference for future spectroscopy experiments or dynamical calculations of the molecule.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No 11447148
文摘We give a detailed examination of potential energy curves of the singlet and triplet states of CFC1 correlated with the lowest three dissociation limits. The calculations are carried out at the internally contracted multi- reference configuration interaction/cc-pV（T＋d）Z level with the other two geometric parameters fixed at the state equilibrium conformation. The vertical transition energy, the oscillator strength, the main configuration and the electron transition are also investigated at the same level.
文摘The Hartree-Fock equation is non-linear and has, in principle, multiple solutions. The ωth HF extreme and its associated virtual spin-orbitals furnish an orthogonal base Bω of the full configuration interaction space. Although all Bω bases generate the same CI space, the corresponding configurations of each Bω base have distinct quantum-mechanical information contents. In previous works, we have introduced a multi-reference configuration interaction method, based on the multiple extremes of the Hartree-Fock problem. This method was applied to calculate the permanent electrical dipole and quadrupole moments of some small molecules using minimal and double, triple and polarized double-zeta bases. In all cases were possible, using a reduced number of configurations, to obtain dipole and quadrupole moments in close agreement with the experimental values and energies without compromising the energy of the state function. These results show the positive effect of the use of the multi-reference Hartree-Fock bases that allowed a better extraction of quantum mechanical information from the several Bω bases. But to extend these ideas for larger systems and atomic bases, it is necessary to develop criteria to build the multireference Hartree-Fock bases. In this project, we are beginning a study of the non-uniform distribution of quantum-mechanical information content of the Bω bases, searching identify the factors that allowed obtain the good results cited
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11304185 and 11074151)
文摘The potential energy curves（PECs） of the first electronic excited state of S2（a^1△g） are calculated employing a multi-reference configuration interaction method with the Davidson correction in combination with a series of correlationconsistent basis sets from Dunning： aug-cc-p VX Z（X = T, Q, 5, 6）. In order to obtain PECs with high accuracy, PECs calculated with aug-cc-p V（Q, 5）Z basis sets are extrapolated to the complete basis set limit. The resulting PECs are then fitted to the analytical potential energy function（APEF） using the extended Hartree–Fock approximate correlation energy method. By utilizing the fitted APEF, accurate and reliable spectroscopic parameters are obtained, which are consistent with both experimental and theoretical results. By solving the Schr o¨dinger equation numerically with the APEFs obtained at the AV6 Z and the extrapolated AV（Q, 5）Z level of theory, we calculate the complete set of vibrational levels, classical turning points, inertial rotation and centrifugal distortion constants.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11304185 and 11074151)China Postdoctoral Science Foundation(Grant No.2014M561957)+1 种基金the Postdoctoral Innovation Project of Shandong Province,China(Grant No.201402013)the Shandong Provincial Natural Science Foundation,China(Grant No.ZR2014AM022)
文摘A globally accurate potential energy surface is reported for the electronic ground-state H2O＋. The ab initio energies utilized to map the potential energy surface are calculated at the multireference configuration interaction method employing the aug-cc-pVQZ basis set and the full valence complete active space wave function as reference. In order to improve accu- racy of the resulting raw ab initio energies, they are then extrapolated to the complete basis set limit and most importantly to the full configuration-interaction limit by semiempirically correcting the dynamical correlation using the double many- body expansion-scaled external correlation method. The topographical features of the current potential energy surface were examined in detail, which agree nicely with those of other theoretical work.
基金supported by the National Natural Science Foundation of China(Grant Nos.11174117 and 11374132)the Program for Scientific Research Innovation Team in Colleges and Universities of Shandong Province,China
文摘The potential energy curves （PECs） of X2∑ and A2П states of the CN molecule have been calculated with the multi- reference configuration interaction method and the aug-cc-pwCVSZ basis set. Based on the PECs, all of the vibrational and rotational levels of the 13C14N molecule are obtained by solving the Schrrdinger equation of the molecular nuclear motion. The spectroscopic parameters are determined by fitting the Dunham coefficients with the levels. Both the levels and the spectroscopic parameters are in good qualitative agreement with the experimental data available. The analytical potential energy functions are also deduced from the calculated PECs. The present results can provide a helpful reference for future spectroscopy experiments or dynamical calculations of the molecule.
