High-level ab initio calculations of aluminum monoiodide(AlI) molecule are performed by utilizing the multireference configuration interaction plus Davidson correction(MRCI+Q) method. The core-valence correlation(CV) ...High-level ab initio calculations of aluminum monoiodide(AlI) molecule are performed by utilizing the multireference configuration interaction plus Davidson correction(MRCI+Q) method. The core-valence correlation(CV) and spin–orbit coupling(SOC) effect are considered. The adiabatic potential energy curves(PECs) of a total of 13 Λ–S states and 24 ? states are computed. The spectroscopic constants of bound states are determined, which are in accordance with the results of the available experimental and theoretical studies. The interactions between the Λ–S states are analyzed with the aid of the spin–orbit matrix elements. Finally, the transition properties including transition dipole moment(TDM),Frank–Condon factors(FCF) and radiative lifetime are obtained based on the computed PEC. Our study sheds light on the electronic structure and spectroscopy of low-lying electronic states of the AlI molecule.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
The potential energy curves （PECs） of three low-lying electronic states （X^3∑, a^1△, and a^3△） of SO radical have been studied by ab initio quantum chemical method. The calcula- tions were carried out with the ...The potential energy curves （PECs） of three low-lying electronic states （X^3∑, a^1△, and a^3△） of SO radical have been studied by ab initio quantum chemical method. The calcula- tions were carried out with the full valence complete active space self-consistent field method followed by the highly accurate valence internally contracted multireference configuration in- teraction （MRCI） approach in combination with correlation-consistent basis sets. Effects of the core-valence correlation and relativistic corrections on the PECs are taken into account. The core-valence correlation correction is carried out with the cc-pCVDZ basis set. The way to consider the relativistic correction is to use the second-order Douglas-Kroll Hamiltonian approximation, and the correction is performed at the level of cc-pV5Z basis set. To obtain more reliable results, the PECs determined by the MRCI calculations are also corrected for size-extensivity errors by means of the Davidson modification （MRCI＋Q）. These PECs are extrapolated to the complete basis set limit by the two-point energy extrapolation scheme. With these PECs, the spectroscopic parameters are determined.展开更多
基金Project supported by the National Key Research and Development Program of China(Grant No.2017YFA0403300)the National Natural Science Foundation of China(Grant Nos.11874179,11574114,and 11874177)the Natural Science Foundation of Jilin Province,China(Grant Nos.20180101289JC)
文摘High-level ab initio calculations of aluminum monoiodide(AlI) molecule are performed by utilizing the multireference configuration interaction plus Davidson correction(MRCI+Q) method. The core-valence correlation(CV) and spin–orbit coupling(SOC) effect are considered. The adiabatic potential energy curves(PECs) of a total of 13 Λ–S states and 24 ? states are computed. The spectroscopic constants of bound states are determined, which are in accordance with the results of the available experimental and theoretical studies. The interactions between the Λ–S states are analyzed with the aid of the spin–orbit matrix elements. Finally, the transition properties including transition dipole moment(TDM),Frank–Condon factors(FCF) and radiative lifetime are obtained based on the computed PEC. Our study sheds light on the electronic structure and spectroscopy of low-lying electronic states of the AlI molecule.
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.
文摘The potential energy curves （PECs） of three low-lying electronic states （X^3∑, a^1△, and a^3△） of SO radical have been studied by ab initio quantum chemical method. The calcula- tions were carried out with the full valence complete active space self-consistent field method followed by the highly accurate valence internally contracted multireference configuration in- teraction （MRCI） approach in combination with correlation-consistent basis sets. Effects of the core-valence correlation and relativistic corrections on the PECs are taken into account. The core-valence correlation correction is carried out with the cc-pCVDZ basis set. The way to consider the relativistic correction is to use the second-order Douglas-Kroll Hamiltonian approximation, and the correction is performed at the level of cc-pV5Z basis set. To obtain more reliable results, the PECs determined by the MRCI calculations are also corrected for size-extensivity errors by means of the Davidson modification （MRCI＋Q）. These PECs are extrapolated to the complete basis set limit by the two-point energy extrapolation scheme. With these PECs, the spectroscopic parameters are determined.
