液体溶液中非线性光谱信号的非微扰计算。

A nonperturbative calculation of nonlinear spectroscopic signals in liquid solution.

作者信息

Ka Being J, Geva Eitan

机构信息

Department of Chemistry, University of Michigan, 930 North University, Ann Arbor, Michigan 48109-1055, USA.

出版信息

J Chem Phys. 2006 Dec 7;125(21):214501. doi: 10.1063/1.2359440.

DOI:10.1063/1.2359440

PMID:17166027

Abstract

Nonlinear spectroscopic signals in liquid solution were calculated without treating the field-matter interaction in a perturbative manner. The calculation is based on the assumption that the intermolecular degrees of freedom can be treated classically, while the time evolution of the electronic state is treated quantum mechanically. The calculated overall electronic polarization is then resolved into its directional components via the method of Seidner et al. [J. Chem. Phys. 103, 3998 (1995)]. It is shown that the time dependence of the directional components is independent of laser intensity in the impulsive pulse regime, which allows for flexibility in choosing the procedure for calculating optical response functions. The utility and robustness of the nonperturbative procedure is demonstrated in the case of a two-state chromophore solvated in a monoatomic liquid, by calculating nonlinear time-domain signals in the strong-field, weak-field, impulsive, and nonimpulsive regimes.

摘要

在不采用微扰方式处理场-物质相互作用的情况下，计算了液体溶液中的非线性光谱信号。该计算基于这样的假设：分子间自由度可经典处理，而电子态的时间演化则用量子力学方法处理。然后，通过Seidner等人[《化学物理杂志》103, 3998 (1995)]的方法，将计算得到的总电子极化分解为其方向分量。结果表明，在脉冲 regime 中，方向分量的时间依赖性与激光强度无关，这使得在选择计算光学响应函数的程序时具有灵活性。通过计算强场、弱场、脉冲和非脉冲 regime 中的非线性时域信号，在单原子液体中溶剂化的双态发色团的情况下，证明了非微扰程序的实用性和稳健性。