Carbon monosulfide molecular ion （CS＋）, which plays an important role in various research fields, has long been attracting much interest. Because of the unstable and transient nature of CS＋, its electronic states ...Carbon monosulfide molecular ion （CS＋）, which plays an important role in various research fields, has long been attracting much interest. Because of the unstable and transient nature of CS＋, its electronic states have not been well investigated. In this paper, the electronic states of CS＋ are studied by employing the internally contracted multireference configuration interaction method, and taking into account relativistic effects （scalar plus spin–orbit coupling）. The spin–orbit coupling effects are considered via the state-interacting method with the full Breit–Pauli Hamiltonian. The potential energy curves of 18 Λ–S states correlated with the two lowest dissociation limits of CS＋ molecular ion are calculated, and those of 10 lowest Ω states generated from the 6 lowest Λ–S states are also worked out. The spectroscopic constants of the bound states are evaluated, and they are in good agreement with available experimental results and theoretical values. With the aid of analysis of Λ–S composition of Ω states at different bond lengths, the avoided crossing phenomena in the electronic states of CS＋ are illuminated. Finally, the single ionization spectra of CS （X1Σ＋） populating the CS＋（X2Σ1/2＋, A2Π3/2, A2Π1/2, and B2Σ1/2＋） states are simulated. The vertical ionization potentials for X2Σ1/2＋, A2Π3/2, A2Π1/2, and B2Σ1/2＋ states are calculated to be 11.257, 12.787, 12.827, and 15.860 eV, respectively, which are accurate compared with previous experimental results, within an error margin of 0.08 eV^0.2 eV.展开更多
Theoretical investigation of low-lying electronic states and B3~u B3∑u^-X3∑g^-transition properties of selenium dimer using size-extensivity singly and doubly excitation multireference configuration interaction theo...Theoretical investigation of low-lying electronic states and B3~u B3∑u^-X3∑g^-transition properties of selenium dimer using size-extensivity singly and doubly excitation multireference configuration interaction theory with nonrelativistic all-electron basis set and relativistic effective core potential plus its split valence basis set is presented in this paper. The spectroscopic constants of ten low-lying A-S bound states have been obtained and compared with experiments. Spin-orbit calculations for coupling between B3∑u^ sates and repulsive 1Лu, 5Лu states have been made to interpret the predissociation mechanisms of the B3∑u^- state. The lifetimes of B3∑u^-（v= 0 - 6） have been calculated with scalar relativistic effects included or excluded, respectively, and reasonably agree with experimental values.展开更多
Photoionization time delays have been studied in many streaking experiments in which an attosecond pulse is used to ionize the atomic or solid state target in the presence of a dressing infrared laser field. Among the...Photoionization time delays have been studied in many streaking experiments in which an attosecond pulse is used to ionize the atomic or solid state target in the presence of a dressing infrared laser field. Among the methods of extracting the time delay from the streaking spectrogram, the simplest one is to calculate the first moment of the spectrogram and to measure its offset relative to the vector potential of the infrared field. The first moment method has been used in many theoretical simulations and analysis of experimental data, but the meaning of this offset needs to be investigated. We simulate the spectrograms and compare the extracted time delay from the first moment with the input Wigner delay. In this study, we show that the first moment method is valid only when the group delay dispersions corresponding to both the spectral phase of the attosecond pulse and the phase of the single-photon transition dipole matrix element of the target are small. Under such circumstance, the electron wave packet behaves like a classical particle and the extracted time delay can be related to a group delay in the photoionization process. To avoid ambiguity and confusion, we also suggest that the photoionization time delay be replaced by photoionization group delay and the Wigner time delay be replaced by Wigner group delay.展开更多
A computational scheme for accurate spectroscopic constants was presented in this work and applied to the lowest two electronic states of sulfur dimer. A high-level ab initio calculation utilizing explicitly correlate...A computational scheme for accurate spectroscopic constants was presented in this work and applied to the lowest two electronic states of sulfur dimer. A high-level ab initio calculation utilizing explicitly correlated multireference con- figuration interaction method （MRCI-F12） was performed to compute the potential energy curves （PECs） of the ground triplet X3Eg and first excited singlet alAg states of sulfur dimer with cc-pCVXZ-F12（X = T, Q） basis sets. The effects of Davidson modification, core-valence correlation correction, and scalar relativistic correction on the spectroscopic con- stants were examined. The vibration-rotation spectra of the two electronic states were provided. Our computational results show excellent agreement with existing available experimental values, and the errors of main spectroscopic constants are within 0.1% order of magnitude. The present computational scheme is cheap and accurate, which is expected for extensive investigations on the potential energy curves or surfaces of other molecular systems.展开更多
基金Project supported by the National Basic Research Program of China(973 Program)(Grant No.2013CB922200)the National Natural Science Foundation of China(Grant Nos.11034003,11074095,and 11274140)+1 种基金the Natural Science Foundation of Heilongjiang Province,China(Grant No.QC2011C092)the Scientific Research Fund of Heilongjiang Provincial Education Department,China(Grant No.12531751)
文摘Carbon monosulfide molecular ion （CS＋）, which plays an important role in various research fields, has long been attracting much interest. Because of the unstable and transient nature of CS＋, its electronic states have not been well investigated. In this paper, the electronic states of CS＋ are studied by employing the internally contracted multireference configuration interaction method, and taking into account relativistic effects （scalar plus spin–orbit coupling）. The spin–orbit coupling effects are considered via the state-interacting method with the full Breit–Pauli Hamiltonian. The potential energy curves of 18 Λ–S states correlated with the two lowest dissociation limits of CS＋ molecular ion are calculated, and those of 10 lowest Ω states generated from the 6 lowest Λ–S states are also worked out. The spectroscopic constants of the bound states are evaluated, and they are in good agreement with available experimental results and theoretical values. With the aid of analysis of Λ–S composition of Ω states at different bond lengths, the avoided crossing phenomena in the electronic states of CS＋ are illuminated. Finally, the single ionization spectra of CS （X1Σ＋） populating the CS＋（X2Σ1/2＋, A2Π3/2, A2Π1/2, and B2Σ1/2＋） states are simulated. The vertical ionization potentials for X2Σ1/2＋, A2Π3/2, A2Π1/2, and B2Σ1/2＋ states are calculated to be 11.257, 12.787, 12.827, and 15.860 eV, respectively, which are accurate compared with previous experimental results, within an error margin of 0.08 eV^0.2 eV.
基金supported by the National Natural Science Foundation of China (Grant No.10604022)Chinese National Fusion Project for ITER (Grant No.2010GB104003)the Fundamental Research Funds for the Central Universities (Grant No.200903369)
文摘Theoretical investigation of low-lying electronic states and B3~u B3∑u^-X3∑g^-transition properties of selenium dimer using size-extensivity singly and doubly excitation multireference configuration interaction theory with nonrelativistic all-electron basis set and relativistic effective core potential plus its split valence basis set is presented in this paper. The spectroscopic constants of ten low-lying A-S bound states have been obtained and compared with experiments. Spin-orbit calculations for coupling between B3∑u^ sates and repulsive 1Лu, 5Лu states have been made to interpret the predissociation mechanisms of the B3∑u^- state. The lifetimes of B3∑u^-（v= 0 - 6） have been calculated with scalar relativistic effects included or excluded, respectively, and reasonably agree with experimental values.
基金Project supported by the Talent Introduction Foundation of Qiannan Normal University of Nationalities,China(Grant No.qnsyrc201619)Natural Science Foundation of Guizhou Provincial Education Department for Young Talents,China(Grant No.Qian Education Contract KY[2017]339)Chemical Sciences,Geosciences and Biosciences Division,Office of Basic Energy Sciences,Office of Science,U.S.Department of Energy(Grant No.DE-FG02-86ER13491)
文摘Photoionization time delays have been studied in many streaking experiments in which an attosecond pulse is used to ionize the atomic or solid state target in the presence of a dressing infrared laser field. Among the methods of extracting the time delay from the streaking spectrogram, the simplest one is to calculate the first moment of the spectrogram and to measure its offset relative to the vector potential of the infrared field. The first moment method has been used in many theoretical simulations and analysis of experimental data, but the meaning of this offset needs to be investigated. We simulate the spectrograms and compare the extracted time delay from the first moment with the input Wigner delay. In this study, we show that the first moment method is valid only when the group delay dispersions corresponding to both the spectral phase of the attosecond pulse and the phase of the single-photon transition dipole matrix element of the target are small. Under such circumstance, the electron wave packet behaves like a classical particle and the extracted time delay can be related to a group delay in the photoionization process. To avoid ambiguity and confusion, we also suggest that the photoionization time delay be replaced by photoionization group delay and the Wigner time delay be replaced by Wigner group delay.
基金supported by the National Natural Science Foundation of China(Grand No.11574114)the Natural Science Foundation of Jilin Province,China(Grand No.20150101003JC)
文摘A computational scheme for accurate spectroscopic constants was presented in this work and applied to the lowest two electronic states of sulfur dimer. A high-level ab initio calculation utilizing explicitly correlated multireference con- figuration interaction method （MRCI-F12） was performed to compute the potential energy curves （PECs） of the ground triplet X3Eg and first excited singlet alAg states of sulfur dimer with cc-pCVXZ-F12（X = T, Q） basis sets. The effects of Davidson modification, core-valence correlation correction, and scalar relativistic correction on the spectroscopic con- stants were examined. The vibration-rotation spectra of the two electronic states were provided. Our computational results show excellent agreement with existing available experimental values, and the errors of main spectroscopic constants are within 0.1% order of magnitude. The present computational scheme is cheap and accurate, which is expected for extensive investigations on the potential energy curves or surfaces of other molecular systems.
