Saito Shinji, Ohmine Iwao
Department of Chemistry, Faculty of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8602, Japan.
Phys Rev Lett. 2002 May 20;88(20):207401. doi: 10.1103/PhysRevLett.88.207401. Epub 2002 Apr 30.
The off-resonant fifth-order response functions for two-dimensional (2D) Raman spectroscopy of molecular liquids CS2 and H2O are investigated by using molecular dynamics calculation. This spectroscopy, able to deal with a phase space dynamics, shows the existence of nodal lines in several polarization tensor elements [see L. Kaufman et al., Phys. Rev. Lett. 88, 207402 (2002) for experimental results]. The nodal property is found to arise from the dynamical couplings among rotational modes, not accounted for in a normal mode picture. The effects of anharmonicities and "mode coupling through polarizability" are also investigated by comparing the 2D Raman signal with a constant temperature velocity reassignment echo method.
通过分子动力学计算研究了分子液体CS₂和H₂O的二维（2D）拉曼光谱的非共振五阶响应函数。这种光谱能够处理相空间动力学，显示出在几个极化张量元素中存在节线[见L. Kaufman等人，《物理评论快报》88, 207402 (2002)中的实验结果]。发现节线特性源于转动模式之间的动力学耦合，这在简正模式图像中未被考虑。还通过将二维拉曼信号与恒温速度重新分配回波方法进行比较，研究了非谐性和“通过极化率的模式耦合”的影响。
