Direct Correlation between Short-Range Vibrational Spectral Diffusion and Localized Ion-Cage Dynamics of Water-in-Salt Electrolytes

Biswas, Aritri and Mallik, Bhabani Shankar (2023) Direct Correlation between Short-Range Vibrational Spectral Diffusion and Localized Ion-Cage Dynamics of Water-in-Salt Electrolytes. The Journal of Physical Chemistry B, 127 (1). pp. 236-248. ISSN 1520-6106

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Abstract

The molecular dynamics simulations of a “water-in-salt” electrolyte, lithium bis(trifluoromethyl sulfonyl) imide (LiNTf2), with a varying concentration range of 3 to 20 m were performed to establish a direct connection between a dynamic property like the ion-cage lifetime with the short-range vibrational stretching frequency shift of the used probe, HOD. The properties reported here are compared to that obtained from experiments performed at the same concentrations. The time-series wavelet transform was adopted as a preferable mathematical tool for calculating the instantaneous fluctuating frequencies of the probe O-D stretch mode and the concentration-dependent vibrational stretch spectral signature based on the variable functions associated with a particular chemical bond derived from classical molecular dynamics trajectories. The decay time constants of frequency fluctuations and the lifetime of the ion cage (τIC) were estimated as a function of salt concentration. Herein, we emphasize the correlation between the slowest time constant (τ3) of the decay of O-D stretch frequency fluctuations and the timescales associated with the lifetime of ion cages (τIC). The results exhibit that the existing relationships were also concentration-dependent. Therefore, this study highlights the connection between the ionic motions that regulate the overall system dynamics with the short-range vibrational frequency shift of the used probe, which was used similar to experiments. It also provides an understanding of the interionic interactions and the dynamical and spectral properties of the electrolytic mixtures. We establish a direct correlation between short-range frequency profile and localized ion-cage lifetime, which can fill the gap of understanding between viscosity, vibrational frequency, and ion-cage dynamics of electrolytes.

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IITH Creators:

IITH Creators	ORCiD
Mallik, Bhabani Shankar	http://orcid.org/0000-0001-9657-1497

Item Type:

Article

Uncontrolled Keywords:

Hydrogen Bonding; Ions; Sodium Chloride; Vibration; Water;Electrolytes; Molecular dynamics; Probes; Wavelet transforms;ion; sodium chloride; water;Cage dynamics; Concentration ranges; Concentration-dependent; Dynamics simulation; Frequency fluctuation; Localised; Salt electrolytes; Spectral diffusion; Sulfonyl imide; Trifluoromethyl;chemistry; hydrogen bond; vibration;Ions

Subjects:

Chemistry
Chemistry > Physical chemistry
Chemistry > Organic chemistry
Chemistry > Crystallography

Divisions:

Department of Chemistry

Depositing User:

Mr Nigam Prasad Bisoyi

Date Deposited:

16 Aug 2023 11:04

Last Modified:

16 Aug 2023 11:04

URI:

http://raiithold.iith.ac.in/id/eprint/11542