Comment on a critique of the instantaneous normal mode (INM) approach to diffusion [J. Chem. Phys. 107, 4618 (1997)]

摘要: A critique of the instantaneous normal mode (INM) theory diffusion by Gezelter, Rabani, and Berne (GRB) [J. Chem. Phys. 107, 4618 (1997)] is analyzed. GRB assert that imaginary-frequency INM are corrupted with modes unrelated to barrier crossing, proposals for removing such nondiffusive (ND) inadequate, thus cannot be used predict self-diffusion constant, D. In rebuttal it argued Lennard-Jones, system studied GRB, anamolously rich in ND modes. molecular liquids shown behave as excellent indicators crossing. Even LJ ND-INM, while plentiful, do not dominate D except supercooled near Tg crystal; hence many successes theories already reported LJ. Agreement simulated Im-ω densities states calculations modeling excitations soft potential model also indicate reflect energy landscape liquids.