物理化学学报 >> 2010, Vol. 26 >> Issue (03): 740-744.doi: 10.3866/PKU.WHXB20100240

量子化学及计算化学 上一篇    下一篇

NaC分子基态及其低电子激发态

陈恒杰, 唐海燕, 程新路, 王全武   

  1. 重庆科技学院数理系, 重庆 401331; 四川大学原子与分子物理研究所, 成都 610065
  • 收稿日期:2009-10-12 修回日期:2009-12-17 发布日期:2010-03-03
  • 通讯作者: 陈恒杰 E-mail:nwwolfchj@gmail.com

Ground and Low-Lying Excited States of NaC Molecule

CHEN Heng-Jie, TANG Hai-Yan, CHENG Xin-Lu, WANG Quan-Wu   

  1. Department of Mathematics and Physics, Chongqin University of Science and Technology, Chongqin 401331, P. R. China; Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, P. R. China
  • Received:2009-10-12 Revised:2009-12-17 Published:2010-03-03
  • Contact: CHEN Heng-Jie E-mail:nwwolfchj@gmail.com

摘要:

运用包含Davidson修正的多参考组态相互作用(MRCI+Q)方法结合6-311++G(3df,3pd)基组计算了NaC分子基态(X4∑)以及三个低电子激发态(a2Π, b2∑, A4Π)的势能曲线(PECs), 确定出相应态的平衡键长Re和垂直激发能Te. 然后将PECs拟合到Murrel-Sorbie(MS)解析势能函数形式, 继而获得各态的光谱数据: 谐振频率ωe、离解能De、非谐性常数ωeΧe、转动常数Be、Drot和振转耦合常数αe. 计算结果表明: X4∑、a2Π、b2∑是三个束缚电子态. 基态X4∑的平衡键长为0.2259 nm, 谐振频率为431 cm-1, 离解能为1.92 eV, 目前计算值与实验结果和其它理论值一致. a2Π和b2∑激发态的核间距、谐振频率分别为0.2447、0.2369 nm 和329、335 cm-1, Te分别为1.58 和1.75eV, De则为0.71和0.42 eV. A4Π态为排斥态, 其相对基态的垂直激发能为2.48 eV. 通过求解核运动的薛定谔方程找到了转动量子数J=0时NaC分子三个低电子态(X4∑, a2Π, b2∑)的全部振动能级和转动惯量.

关键词: 多参考组态相互作用, NaC, 光谱常数, 解析势能函数, 振动能级

Abstract:

Potential energy curves (PECs) for the ground electronic state (X4∑) and the three lowest excited electronic states (a2Π, b2∑, A4Π) of NaCmolecule were calculated using the multi-configuration reference single and double excited configuration interactionmethod, including Davidson's corrections for quadruple excitations (MRCI+Q). The equilibrium bond length Re and the vertical excited energy Te were determined directly and the PECs were fitted to an analytical Murrell-Sorbie (MS) potential function to determine the spectroscopic parameters, which were the rotation coupling constant ωe, dissociation energy De, the anharmonic constant ωe Χe, the equilibrium rotation constant Be and Drot, and the vibration-rotation coupling constant αe. These values were also compared and were in agreement with other theoretical and experimental results currently available. It is evident that the X4∑, a2Π, and b2∑ states are bound. We found that in the ground state X4∑, Re was 0.2259 nm, ωe was 431 cm-1, and De was 1.92 eV, while in the excited states a2Πand b2∑, Re and ωe were 0.2447, 0.2369 nm and 329, 335 cm-1, respectively. Te was found to be 1.58 and 1.75 eV and De was 0.71 and 0.42 eV. A4Πis a repulsive excited state when Te is 2.48 eV relative to the ground state. By solving the radial Schrodinger equation of nuclear motion the vibration levels and inertial rotation constant at rotational quantum number J=0 are reported for the X4∑, a2Π, and b2∑ states.

Key words: Multi-reference configuration interaction, NaC, Spectroscopic constant, Analytical potential energy function, Vibrational level

MSC2000: 

  • O641