Perturbation Approach for Computing Infrared Spectra of the Local Mode of Probe Molecules

• DOI: 10.1021/acs.jctc.6b00733
• Publication Date: 2016-11-22T21:23:04Z
• Authors: Rui-Jie Xue; Adam Grofe; He Yin; Zexing Qu; Jiali Gao; Hui Li
• Keywords: Mode (computer interface)

Linear and two-dimensional infrared (IR) spectroscopy of site-specific probe molecules provides an opportunity to gain a molecular-level understanding the local hydrogen-bonding network, conformational dynamics, long-range electrostatic interactions in condensed-phase biological systems. A challenge computation is determine time-dependent vibrational frequencies that incorporate explicitly both nuclear quantum effects motions electronic structural representation potential energy surface. In this paper, perturbation (QVP) method described for efficiently determining instantaneous frequency chromophore molecular dynamics simulations. Computational efficiency achieved through use (a) discrete variable wave functions, (b) theory evaluate shifts due solvent dynamic fluctuations, (c) combined QM/MM It was found first-order sufficiently accurate, enabling be obtained on fly dynamics. The QVP illustrated mode-specific linear 2D-IR spectra H-Cl stretching HCl-water clusters carbonyl vibration acetone aqueous solution. To further reduce computational cost, hybrid strategy proposed, it computed spectral peak position line shape are agreement with experimental results. addition, anharmonicity significant mode, enhance anharmonic effects. present complements other approaches, including path integral-based represents major improvement over electrostatics-based spectroscopic mapping procedures.