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Vibrational echo spectroscopy of aqueous sodium bromide solutions from first principles simulations
Author(s) -
Ojha Deepak,
Chandra Amalendu
Publication year - 2019
Publication title -
journal of computational chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.907
H-Index - 188
eISSN - 1096-987X
pISSN - 0192-8651
DOI - 10.1002/jcc.25860
Subject(s) - chemistry , deuterium , spectroscopy , diffusion , ionic bonding , atomic physics , ab initio , molecular physics , nuclear magnetic resonance , ion , physics , thermodynamics , organic chemistry , quantum mechanics
A theoretical study of the time‐dependent vibrational echo spectroscopy of sodium bromide solutions in deuterated water at two different concentrations of 0.5 and 5.0 M and at temperatures of 300 and 350 K is presented using the method of ab initio molecular dynamics simulations. The instantaneous fluctuations in frequencies of local OD stretch modes are calculated using time‐series analysis of the simulated trajectories. The third‐order polarization and intensities of three pulse photon‐echo are calculated from ab initio simulations. The timescales of vibrational spectral diffusion are determined from the frequency time correlation functions (FTCF) and short‐time slope of three pulse photon echo (S3PE) calculated within the second‐order cumulant and Condon approximations. It is found that under ambient conditions, the rate of vibrational spectral diffusion becomes slower with increase in ionic concentration. Decay of S3PE calculated for different systems give timescales, which are in close agreement with those of FTCF and also with the results of experimental time‐dependent vibrational spectroscopic experiments. © 2019 Wiley Periodicals, Inc.