CH_3I分子的光吸收谱的多参考组态计算

Multireference calculation of absorption spectra of methyl iodide

采用完全活化空间多组态自洽场方法优化了CH3I分子基态的几何结构.根据二阶自旋-轨道多参考组态相互作用理论计算了CH3I分子的势能曲线,并计算了该分子较低几个激发态的垂直激发能、CH3I分子的吸收谱.讨论了温度对吸收谱的影响,并估计了激发态碘原子I*(2P1/2)的量子产额,结果表明实验测量值与理论计算值吻合得很好.

Equilibrium geometries of CH3I molecule are optimized with complete active space self- consistent field（CASSCF） method. The effective potential energy curves correlated to ^2I3^03/2 and ^2I^°1/2° atom limits are calculated using second order spin-obit multiconfigurational quasidegenerate perturbation theory （SO-MCQDPT）, the low-lying excited of CH3I molecule are calculated and the result show that theoretical calculation was in good agreement with experimental values. The absorption spectra are stimulated and the quantum yields of 2i°1/2° atom are estimated. The present calculations can be used to interpret the experimental results.