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Biswas A, Mallik BS. Multiple Ensembles of the Hydrogen-bonded Network in Ethylammonium Nitrate versus Water from Vibrational Spectral Dynamics of SCN- Probe. Chemphyschem 2022; 23:e202200497. [PMID: 35965410 DOI: 10.1002/cphc.202200497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 08/05/2022] [Indexed: 11/12/2022]
Abstract
We performed classical molecular dynamics simulations to monitor the structural interactions and ultrafast dynamical and spectral response in the protic ionic liquid, ethylammonium nitrate (EAN) and water using the nitrile stretching mode of thiocyanate ion (SCN-) as the vibrational probe. The normalized stretch frequency distribution of nitrile stretch of SCN- attains an asymmetric shape in EAN, indicating the existence of more than one hydrogen-bonding environment in EAN. We computed the 2D IR spectrum from classical trajectories, applying the response function formalism. Spectral diffusion dynamics in EAN undergo an initial rattling of the SCN - inside the local ion-cage occurring at a timescale of 0.10 ps, followed by the breakup of the ion-cage activating molecular diffusion at 7.86 ps timescale. In contrast, the dynamics of structural reorganization occur at a timescale of 0.58 ps in H 2 O. Hence, the time dependence of the frequency-frequency correlation function decay hints at the local molecular structure and ultrafast ion dynamics of the SCN - probe. The loss of frequency correlation read from the peak shape changes in the 2D correlation spectrum as a function of waiting time is faster in H 2 O than in EAN due to the enhanced structural ordering and higher viscosity of the latter. We provide an atomic-level interpretation of the solvation environment around SCN - in EAN and water, which indicates the multiple ensembles of the hydrogen bond network in EAN.
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Affiliation(s)
- Aritri Biswas
- IITH: Indian Institute of Technology Hyderabad, Chemistry, INDIA
| | - Bhabani S Mallik
- IITH: Indian Institute of Technology Hyderabad, Chemistry, Kandi, 502285, Sangareddy, INDIA
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Biswas A, Mallik BS. Revisiting OD-stretching dynamics of methanol‑d4, ethanol-d6 and dilute HOD/H2O mixture with predefined potentials and wavelet transform spectra. Chem Phys 2022. [DOI: 10.1016/j.chemphys.2021.111385] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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A combined experimental and computational investigation of the binary mixtures of 2-methylcyclohexanol and isobutanol. Struct Chem 2021. [DOI: 10.1007/s11224-020-01709-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Biswas A, Mallik BS. Dynamics of Ionic Liquid through Intrinsic Vibrational Probes Using the Dispersion-Corrected DFT Functionals. J Phys Chem B 2021; 125:6994-7008. [PMID: 34142827 DOI: 10.1021/acs.jpcb.1c04960] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
First principles molecular dynamics simulations have been utilized to study the spectral properties of the protic ionic liquid, methylammonium formate (MAF). All simulations were performed using density functional theory (DFT) and various van der Waals-corrected exchange-correlation functionals. We calculated the vibrational stretch frequency distributions, determined the time-frequency correlations of the intrinsic vibrational probes, the N-H and C-O modes in MAF, and the frequency-structure correlations. We also estimated the average hydrogen-bond lifetimes and orientation dynamics to capture the ultrafast spectral response. The spectroscopic signature of the N-H stretching vibrations using the Becke-Lee-Yang-Parr (BLYP) and Perdew-Burke-Ernzerhof (PBE) functionals displays a spectral shift in the lower frequency side, suggesting stronger hydrogen-bonding interactions represented by the gradient approximation functionals than the van der Waals (vdW)-corrected simulations. The carboxylate frequency profiles with the dispersion-corrected representations are almost similar without a significant difference in the normalized distributions. Besides, the COO stretching frequencies at the peak maxima positions of the PBE functionals exhibit a lesser deviation from the experimental data. Spectral diffusion dynamics of the intrinsic vibrational probes on the cationic and anionic sites of the ionic liquid proceed through a short time relaxation of the intact hydrogen bonds followed by an intermediate time constant and a longer time decay indicating the switchover of hydrogen bonds. Dispersion-corrected atom-centered one-electron potential (DCACP) correction added to the BLYP system slows down the picosecond time scales of frequency correlation and the time constants of rotational motion, lengthening the overall system dynamics. The observed trends in the time-dependent decays of frequency fluctuations and the orientation autocorrelation functions correlate with the structural interactions in liquid MAF and hydrogen-bond dynamics. In this study, we examine the predictions made by different density functional treatments comparing the results of the uncorrected BLYP and PBE representations with the semiempirical vdW methods of Grimme and matching our calculated data with the experimental observations.
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Affiliation(s)
- Aritri Biswas
- Department of Chemistry, Indian Institute of Technology Hyderabad, Sangareddy 502285, Telangana, India
| | - Bhabani S Mallik
- Department of Chemistry, Indian Institute of Technology Hyderabad, Sangareddy 502285, Telangana, India
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Biswas A, Mallik BS. Conformation-induced vibrational spectral dynamics of hydrogen peroxide and vicinal water molecules. Phys Chem Chem Phys 2021; 23:6665-6676. [PMID: 33710191 DOI: 10.1039/d0cp06028c] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
We studied the conformation-induced spectral response of water molecules due to site-specific structural alterations of solvated hydrogen peroxide (H2O2) employing DFT-based first principles molecular dynamics (FPMD) simulations. Wavelet transform was used to determine the time-dependent frequencies of the hydroxyls of water molecules and the O-H stretch modes of H2O2. Shifts in the vibrational frequency of the hydrogen-bonded hydroxyls inside the solvation shell of H2O2 support multiple distinctive hydrogen bonding environments. This paper classifies two distinct hydrogen bond types inside the O-OW solvation shell of H2O2, and the dynamical calculations provide a quantitative estimation of the relative hydrogen bond strength. We ascertain the reason for not observing the escape of water molecules from the hydrogen peroxide hydration shell, unlike the solvation shell of ionic solutions and neutral solutes. Besides, we provide a comprehensive analysis of the spectral shifts in the normalized frequency distribution, the time-dependent decay of frequency-frequency correlation functions, and the hydrogen bond length scale fluctuations. We also quantify the relative contribution of the cisoid and transoid conformers affecting the vibrational spectral signature of the vicinal water molecules. While the transoid conformers promote the hydrogen bonding interactions through the oxygen site (OHW), the cisoid conformers facilitate hydrogen peroxide-water hydrogen bond formation through the hydrogen site (HOW). These non-identical hydrogen bond associations stabilize hydrogen peroxide in water.
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Affiliation(s)
- Aritri Biswas
- Department of Chemistry, Indian Institute of Technology Hyderabad, Sangareddy-502285, Telangana, India.
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Biswas S, Mallik BS. Solvent-mediated dynamics and stretching profile of amide modes: QM/MM simulations of N-methylacetamide in ionic and various molecular liquids. J Mol Liq 2020. [DOI: 10.1016/j.molliq.2020.114202] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Biswas A, Mallik BS. Ultrafast Aqueous Dynamics in Concentrated Electrolytic Solutions of Lithium Salt and Ionic Liquid. J Phys Chem B 2020; 124:9898-9912. [DOI: 10.1021/acs.jpcb.0c06221] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Aritri Biswas
- Department of Chemistry, Indian Institute of Technology Hyderabad, Sangareddy 502285, Telangana, India
| | - Bhabani S. Mallik
- Department of Chemistry, Indian Institute of Technology Hyderabad, Sangareddy 502285, Telangana, India
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Yamaoka S, Hyeon-Deuk K. Decelerated Liquid Dynamics Induced by Component-Dependent Supercooling in Hydrogen and Deuterium Quantum Mixtures. J Phys Chem Lett 2020; 11:4186-4192. [PMID: 32375000 DOI: 10.1021/acs.jpclett.0c00801] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Isotopic mixtures of p-H2 and o-D2 molecules have been an attractive binary system because they include two kinds of purely isotopic molecules which possess the same electronic potential but the twice different mass inducing differently pronounced nuclear quantum effects (NQEs). Accessing details of structures and dynamics in such quantum mixtures combining complex molecular dynamics with NQEs of different strengths remains a challenging problem. Taking advantage of the nonempirical molecular dynamics method which describes p-H2 and o-D2 molecules, we found that the liquid dynamics slows down at a specific mixing ratio, which can be connected to the observed anomalous slowdown of crystallization in the quantum mixtures. We attributed the decelerated dynamics to the component-dependent supercooling of p-H2 taking place in the mixtures, demonstrating that there is an optimal mixing ratio to hinder crystallization. The obtained physical insights will help in experimentally controlling and achieving unknown quantum mixtures including superfluid.
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Affiliation(s)
- Shutaro Yamaoka
- Department of Chemistry, Kyoto University, Kyoto 606-8502, Japan
| | - Kim Hyeon-Deuk
- Department of Chemistry, Kyoto University, Kyoto 606-8502, Japan
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Biswas A, Mallik BS. Structure and stretching dynamics of water molecules around an amphiphilic amide from FPMD simulations: A case study of N,N-dimethylformamide. J Mol Liq 2020. [DOI: 10.1016/j.molliq.2020.112524] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Biswas S, Mallik BS. Aqueous hydroxyl group as the vibrational probe to access the hydrophobicity of amide derivatives. J Mol Liq 2020. [DOI: 10.1016/j.molliq.2019.112395] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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An experimental and molecular dynamics simulation study of the structural and thermodynamic properties of the binary mixtures of morpholine and propylene glycol. J Mol Liq 2020. [DOI: 10.1016/j.molliq.2020.112584] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Biswas A, Mallik BS. Distinctive behavior and two-dimensional vibrational dynamics of water molecules inside glycine solvation shell. RSC Adv 2020. [DOI: 10.1039/c9ra10521b] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
We present a first principles molecular dynamics study of a deuterated aqueous solution of a single glycine moiety to explore the structure, dynamics, and two-dimensional infrared spectra of water molecules found in the solvation shell of glycine.
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Affiliation(s)
- Aritri Biswas
- Department of Chemistry
- Indian Institute of Technology Hyderabad
- Sangareddy
- India
| | - Bhabani S. Mallik
- Department of Chemistry
- Indian Institute of Technology Hyderabad
- Sangareddy
- India
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Hydrogen bond dynamics and vibrational spectral diffusion in aqueous solution of formaldehyde: a first principles molecular dynamics study. Theor Chem Acc 2018. [DOI: 10.1007/s00214-018-2333-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Biswas S, Mallik BS. Time-dependent vibrational spectral analysis of first principles trajectory of methylamine with wavelet transform. Phys Chem Chem Phys 2018; 19:9912-9922. [PMID: 28357425 DOI: 10.1039/c7cp00412e] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The fluctuation dynamics of amine stretching frequencies, hydrogen bonds, dangling N-D bonds, and the orientation profile of the amine group of methylamine (MA) were investigated under ambient conditions by means of dispersion-corrected density functional theory-based first principles molecular dynamics (FPMD) simulations. Along with the dynamical properties, various equilibrium properties such as radial distribution function, spatial distribution function, combined radial and angular distribution functions and hydrogen bonding were also calculated. The instantaneous stretching frequencies of amine groups were obtained by wavelet transform of the trajectory obtained from FPMD simulations. The frequency-structure correlation reveals that the amine stretching frequency is weakly correlated with the nearest nitrogen-deuterium distance. The frequency-frequency correlation function has a short time scale of around 110 fs and a longer time scale of about 1.15 ps. It was found that the short time scale originates from the underdamped motion of intact hydrogen bonds of MA pairs. However, the long time scale of the vibrational spectral diffusion of N-D modes is determined by the overall dynamics of hydrogen bonds as well as the dangling ND groups and the inertial rotation of the amine group of the molecule.
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Affiliation(s)
- Sohag Biswas
- Department of Chemistry, Indian Institute of Technology Hyderabad, Kandi, Sangareddy - 502285, Telangana, India.
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Yadav VK. Formaldehyde-mediated spectroscopic properties of heavy water from first principles simulation. COMPUT THEOR CHEM 2017. [DOI: 10.1016/j.comptc.2017.10.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Biswas S, Dasgupta T, Mallik BS. Proton transfer from water to ketyl radical anion: Assessment of critical size of hydrated cluster and free energy barrier in solution from first principles simulations. Chem Phys 2016. [DOI: 10.1016/j.chemphys.2016.08.022] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Molecular dynamics simulations of K+–Cl− ion pair in polar mixtures of acetone and water: Preferential solvation and structural studies. J Mol Liq 2016. [DOI: 10.1016/j.molliq.2015.11.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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