A basic calculation procedure for the MOSMO method under CNDO/2 approximation is presented in this paper,and performed by using the same parameters as those used in the ordinary CNDO/2 LCAO-MO calculation.The calculat...A basic calculation procedure for the MOSMO method under CNDO/2 approximation is presented in this paper,and performed by using the same parameters as those used in the ordinary CNDO/2 LCAO-MO calculation.The calculated results on the whole are close to those obtained by use of the ordinary CNDO/2 LCAO-MO calculation,illustrating that the presented procedure is reasonable.Due to its simplicity,the presented calculation procedure may be feasible even in very large molecular s ystems.展开更多
The localized molecular orbitals and energy levels for four typical conjugated six-membered ring systems C_6H_6, C_3N_3H_3, B_3N_3H_6, and (B_3O_6)^(3-) as well as a non-aromatic reference molecule N_3Cl_6 have been ...The localized molecular orbitals and energy levels for four typical conjugated six-membered ring systems C_6H_6, C_3N_3H_3, B_3N_3H_6, and (B_3O_6)^(3-) as well as a non-aromatic reference molecule N_3Cl_6 have been calculated by using Edmiston-Ruedenberg energy localization technique under the CNDO/2 approximation in order to investigate the nature of aromaticity or quasi-aromaticity of the six-membered ring systems studied. The contour maps for π-type localized MO's (LMO) have been plotted to illustrate the bonding characteristics of the five ring systems studied. These LMO calculations show that for all the conjugated six-membered ring systems considered there exists local delocalization of π-bonds or three-centered and occasionally four-centered two-electron π-bonds in our terminology, and the cooperative effect among these π-bonds leading to the formation of a closed continuous x-conjugation system around the ring, which is necessary for the creation of aromaticity in the systems studied. We have been able to discuss the properties of these three-centered π-bonds in terms of the constituent atoms and electrons and the relevant orbitals involved.展开更多
The molecular geometries,heats of formation and electronic structures of three trinitrobenzenes(1,2,3TNB,1,2,4TNB and 1,3,5TNB)and their chloro derivatives were studied by using the quantum chemical MO AM1 method at t...The molecular geometries,heats of formation and electronic structures of three trinitrobenzenes(1,2,3TNB,1,2,4TNB and 1,3,5TNB)and their chloro derivatives were studied by using the quantum chemical MO AM1 method at the RHF level and ab initio method at the HF/321G level.The decompositions of the title compounds were investigated by using the AM1 method at the UHF level.The decomposition activation energies were obtained and the order of the relative stabilities of the title compounds is found.The substituent effects on the structures and properties and on the decompositions of the title compounds are discussed in the present paper.展开更多
The acidic dissociation constants of dimethoxyhenylfluorone (DMOPF)and dibromo-dimethylaminophenylflurone(Br_2-DMAPF) were determined from a spectrophotometric study, with the results as follows:DMOPF: pk_1=2. 68 pk_2...The acidic dissociation constants of dimethoxyhenylfluorone (DMOPF)and dibromo-dimethylaminophenylflurone(Br_2-DMAPF) were determined from a spectrophotometric study, with the results as follows:DMOPF: pk_1=2. 68 pk_2=6. 79 pk_3=9.25 pk_4=12. 14 Br_2-DMAPF: pk_1=2.08 pk_2=4. 12 pk_3=9. 02 pk_45=11.02 The assignation for the possibly occurred shapes in media of various acidity has been accomplished by comparing the calculated results of π-electronic distribution and maximum absorption wave lengths from Huckel molecular orbital(HMO) method with those from the spectrophotometric ones.展开更多
Catalytic chemiluminescence of over twenty metallic ions in the systemof 2, 6, 7-tihydroxyl-9- (4'-chlorophenyl)-3-fluorone (Cl-PF )-H2O2 has been tested.Trace amount of Co(Ⅱ) strong1y catalysed this chemilumines...Catalytic chemiluminescence of over twenty metallic ions in the systemof 2, 6, 7-tihydroxyl-9- (4'-chlorophenyl)-3-fluorone (Cl-PF )-H2O2 has been tested.Trace amount of Co(Ⅱ) strong1y catalysed this chemiluminescence reaction, especiallyin presence of cationic surfactant cetyltrimethylammonium bromide (CTMAB), andthe chemiluminescence intensity was proportional to the concentraction of Co(Ⅱ) in therange 0. 5~6ng. ml-1 Co(Ⅱ). Two steps could be involved in the chemiluminescentreaction of C1-PF. In alkaline solution, the O2 radical ion should attack an oxygenbridge between the benzene rings of Cl-PF with break in oxygen bridge bond to produce reaction product which is excited by the energy derived from this chemical reaction. The electronic excited state emits the radiation(560 nm) on falling to the groundstate, followed by formation of polyphenol derivatives. the polyphenol derivatives arefurther oxidized to produce chemiluminescence (480 nm) which is due to emission fromsinglet oxygen.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
文摘A basic calculation procedure for the MOSMO method under CNDO/2 approximation is presented in this paper,and performed by using the same parameters as those used in the ordinary CNDO/2 LCAO-MO calculation.The calculated results on the whole are close to those obtained by use of the ordinary CNDO/2 LCAO-MO calculation,illustrating that the presented procedure is reasonable.Due to its simplicity,the presented calculation procedure may be feasible even in very large molecular s ystems.
文摘The localized molecular orbitals and energy levels for four typical conjugated six-membered ring systems C_6H_6, C_3N_3H_3, B_3N_3H_6, and (B_3O_6)^(3-) as well as a non-aromatic reference molecule N_3Cl_6 have been calculated by using Edmiston-Ruedenberg energy localization technique under the CNDO/2 approximation in order to investigate the nature of aromaticity or quasi-aromaticity of the six-membered ring systems studied. The contour maps for π-type localized MO's (LMO) have been plotted to illustrate the bonding characteristics of the five ring systems studied. These LMO calculations show that for all the conjugated six-membered ring systems considered there exists local delocalization of π-bonds or three-centered and occasionally four-centered two-electron π-bonds in our terminology, and the cooperative effect among these π-bonds leading to the formation of a closed continuous x-conjugation system around the ring, which is necessary for the creation of aromaticity in the systems studied. We have been able to discuss the properties of these three-centered π-bonds in terms of the constituent atoms and electrons and the relevant orbitals involved.
文摘The molecular geometries,heats of formation and electronic structures of three trinitrobenzenes(1,2,3TNB,1,2,4TNB and 1,3,5TNB)and their chloro derivatives were studied by using the quantum chemical MO AM1 method at the RHF level and ab initio method at the HF/321G level.The decompositions of the title compounds were investigated by using the AM1 method at the UHF level.The decomposition activation energies were obtained and the order of the relative stabilities of the title compounds is found.The substituent effects on the structures and properties and on the decompositions of the title compounds are discussed in the present paper.
文摘The acidic dissociation constants of dimethoxyhenylfluorone (DMOPF)and dibromo-dimethylaminophenylflurone(Br_2-DMAPF) were determined from a spectrophotometric study, with the results as follows:DMOPF: pk_1=2. 68 pk_2=6. 79 pk_3=9.25 pk_4=12. 14 Br_2-DMAPF: pk_1=2.08 pk_2=4. 12 pk_3=9. 02 pk_45=11.02 The assignation for the possibly occurred shapes in media of various acidity has been accomplished by comparing the calculated results of π-electronic distribution and maximum absorption wave lengths from Huckel molecular orbital(HMO) method with those from the spectrophotometric ones.
文摘Catalytic chemiluminescence of over twenty metallic ions in the systemof 2, 6, 7-tihydroxyl-9- (4'-chlorophenyl)-3-fluorone (Cl-PF )-H2O2 has been tested.Trace amount of Co(Ⅱ) strong1y catalysed this chemiluminescence reaction, especiallyin presence of cationic surfactant cetyltrimethylammonium bromide (CTMAB), andthe chemiluminescence intensity was proportional to the concentraction of Co(Ⅱ) in therange 0. 5~6ng. ml-1 Co(Ⅱ). Two steps could be involved in the chemiluminescentreaction of C1-PF. In alkaline solution, the O2 radical ion should attack an oxygenbridge between the benzene rings of Cl-PF with break in oxygen bridge bond to produce reaction product which is excited by the energy derived from this chemical reaction. The electronic excited state emits the radiation(560 nm) on falling to the groundstate, followed by formation of polyphenol derivatives. the polyphenol derivatives arefurther oxidized to produce chemiluminescence (480 nm) which is due to emission fromsinglet oxygen.
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.
