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De‐Heng Shi Jin‐Ping Zhang Yu‐Fang Liu Jin‐Feng Sun Zun‐Lue Zhu 《International journal of quantum chemistry》2009,109(6):1159-1166
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De-Heng Shi Jin-Ping Zhang Jin-Feng Sun Yu-Fang Liu Zun-Lue Zhu Ben-Hai Yu 《Journal of Molecular Structure》2008,860(1-3):101-105
The coupled-cluster singles-doubles-approximate-triples [CCSD(T)] theory in combination with the correlation-consistent quintuple basis set (aug-cc-pV5Z) is used to investigate the spectroscopic properties of the CH(X2Π) radical. The accurate adiabatic potential energy curve is calculated over the internuclear separation ranging from 0.07 to 2.45 nm and is fitted to the analytic Murrell–Sorbie function, which is employed to determine the spectroscopic parameters, ωeχe, αe and Be. The present De, Re, ωe, ωeχe, αe and Be values are of 3.6261 eV, 0.11199 nm, 2856.312 cm−1, 64.9321 cm−1, 0.5452 cm−1 and 14.457 cm−1, respectively. Excellent agreement is obtained when they are compared with the available measurements. With the potential obtained at the CCSD(T)/aug-cc-pV5Z level of theory, a total of 18 vibrational states is predicted when J = 0 by numerically solving the radial Schrödinger equation of nuclear motion. The complete vibrational levels, classical turning points, inertial rotation and centrifugal distortion constants are reproduced for the CH(X2Π) radical when J = 0 for the first time, which are in good agreement with the available RKR data. 相似文献
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Deheng Shi Hui Liu Jinfeng Sun Jinping Zhang Yufang Liu Zunlue Zhu 《Journal of Molecular Structure》2009,911(1-3):8-12
The equilibrium internuclear separations, harmonic frequencies and potential energy curves of the AsH(X3Σ−) radical have been calculated using the coupled-cluster singles–doubles–approximate-triples [CCSD(T)] theory in combination with the series of correlation-consistent basis sets in the valence range. The potential energy curves are all fitted to the Murrell–Sorbie function, which are used to reproduce the spectroscopic parameters such as De, ωeχe, αe, Be and D0. The present D0, De, Re, ωe, ωeχe, αe and Be obtained at the cc-pV5Z basis set are of 2.8004 eV, 2.9351 eV, 0.15137 nm, 2194.341 cm−1, 43.1235 cm−1, 0.2031 cm−1 and 7.3980 cm−1, respectively, which almost perfectly conform to the measurements. With the potential obtained at the UCCSD(T)/cc-pV5Z level of theory, a total of 18 vibrational states is predicted when the rotational quantum number J is set to equal zero (J = 0) by numerically solving the radial Schrödinger equation of nuclear motion. The complete vibrational levels, classical turning points, inertial rotation and centrifugal distortion constants are determined when J = 0 for the first time, which are in excellent agreement with the experiments. 相似文献
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De‐Heng Shi Wen‐Tao Li Jin‐Feng Sun Zun‐Lue Zhu Yu‐Fang Liu 《International journal of quantum chemistry》2012,112(14):2615-2622
The potential energy curves (PECs) of the X2Π and a4Σ? electronic states of the SiF radical have been studied by an ab initio quantum chemical method. The calculations have been made using the complete active space self‐consistent field (CASSCF) method, which is followed by the valence internally contracted multireference configuration interaction (MRCI) approach in combination with several correlation‐consistent basis sets. The effects on the PECs by the core‐valence correlation and relativistic corrections are included. The way to consider the relativistic correction is to use the third‐order Douglas–Kroll Hamiltonian approximation. The relativistic corrections are made at the level of cc‐pV5Z basis set. The core‐valence correlation corrections are performed using the cc‐pCV5Z 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 total‐energy extrapolation scheme. Using these PECs, the spectroscopic parameters are determined and compared with those reported in the literature. With these PECs obtained by the MRCI+Q/CV+DK+56 calculations, the vibrational levels, inertial rotation, and centrifugal distortion constants of the first 20 vibrational state of each electronic state are calculated when the rotational quantum number J equals zero. Comparison with the Rydberg‐Klein‐Rees (RKR) data shows that the present results are reliable and accurate. The molecular constants of the X2Π and a4Σ? electronic states determined by the MRCI+Q/CV+DK+56 calculations should be good prediction for future laboratory experiment. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2011 相似文献