2003/07/25 by Thomas L. C. Jansen, Thomas la Cour Jansen, Shaul Mukamel +2
Chemistry · Physics and Astronomy · #Molecular spectroscopy and chirality #Spectroscopy and Laser Applications #Spectroscopy and Quantum Chemical Studies #cond-mat.mtrl-sci
paper · pdf · doi:10.48550/arxiv.cond-mat/0307654
arxiv created 2003/07/25 · arxiv updated 2009/12/01
The identification of relevant collective coordinates is crucial for the interpretation of coherent nonlinear spectroscopies of complex molecules and liquids. Using an ℏ expansion of Liouville space generating functions, we show how to factorize multitime nonlinear response functions into products of lower-order correlation functions of collective coordinates, and derive closed expressions for linear, second and third order response functions. In addition to providing systematic quantum corrections, ℏ offers a convenient bookkeeping device even for the purely classical response, since including quantum fluctuations allows to circumvent the expensive computation of stability matrices which is a major bottleneck in Molecular Dynamics (MD) simulations. The existing classical simulation strategies, including Mode-Coupling in k space and in real-space, Langevin equations, and Instantaneous Normal Modes are compared from a unified viewpoint.