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Title: Frequency-Selective Anharmonic Mode Analysis of Thermally Excited Vibrations in Proteins
Low-frequency molecular vibrations at far-infrared frequencies are thermally excited at room temperature. As a consequence, thermal fluctuations are not limited to the immediate vicinity of local minima of the potential energy surface and anharmonic properties cannot be ignored. The latter is particularly relevant in molecules with multiple conformations such as proteins and other biomolecules. However, existing theoretical and computational frameworks for the analysis of molecular vibrations have so far been limited by harmonic or quasi-harmonic approximations, which are ill-suited for the description of anharmonic low-frequency vibrations. Here, we developed a fully anharmonic analysis of molecular vibrations based on a time correlation formalism that eliminates the need for harmonic or quasi-harmonic approximations. We use molecular dynamics simulations of a small protein to demonstrate that this new approach, in contrast to harmonic and quasi-harmonic normal modes, correctly identifies the collective degrees of freedom associated with molecular vibrations at any given frequency. This allows us to unambiguously characterize the anharmonic character of low-frequency vibrations in the far-infrared spectrum.  more » « less
Award ID(s):
2154834
PAR ID:
10502722
Author(s) / Creator(s):
;
Publisher / Repository:
American Chemical Society
Date Published:
Journal Name:
Journal of Chemical Theory and Computation
Volume:
19
Issue:
16
ISSN:
1549-9618
Page Range / eLocation ID:
5481 to 5490
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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