Molecular dynamics simulation and vibrational spectroscopy of molecules (I)—A method of internal coordinate correlation for band assignment

摘要

A method of simulation of vibrational spectra by using the "internal coordinate correlation" based on molecular dynamics algorithms and auto-correlation function has been developed. The internal coordinates, such as bond stretching, bond angle bending, out-of-plane bending and torsion, are treated as the dynamic variables to obtain a density spectrum or the "internal coordinate correlation" spectrum. The advantages of this method are as follows: i) it is easier to assign vibration modes for the density spectra; ii) it simply connects the Fourier transformed "internal coordinate correlation" function to the eigenvectors in normal coordinate analysis; iii) it is a basis for simulating IR and Raman active spectra of a large molecular system,