Water hydrogen-bond dynamics close to hydrophobic and hydrophilic groups

1996 ◽  
Vol 103 ◽  
pp. 29 ◽  
Author(s):  
Alenka Luzar
2010 ◽  
Vol 114 (8) ◽  
pp. 3052-3059 ◽  
Author(s):  
Guillaume Stirnemann ◽  
James T. Hynes ◽  
Damien Laage

2019 ◽  
Author(s):  
Anwesa Karmakar

<p>A series of ab initio MD simulations has been carried out for aqueous azide (N<sub>3</sub><sup>-</sup>) ion solutions at three different densities and at supercritical condition (673 K) using Car-Parrinello molecular dynamics simulation. The time dependent trajectories at three different densities have been used to analyze the hydrogen bond dynamics, residence dynamics, dangling OD bond dynamics and spectral diffusion and underlying connections between them. The time dependent frequency of both the OD and NN stretching mode has been calculated using the time series analysis of the wavelet method. The population correlation function approach has been used to compute the hydrogen bond dynamics, dangling OD bond and residence dynamics of the Sc-water both inside and outside the solvation shell of the ion. The faster hydrogen bond dynamics has been observed in the vicinity of the azide ion, however the calculated OD stretching frequency is found to show red shift in the vicinity of the azide ion indicative to the formation of stronger ion-water hydrogen bond even at the supercritical condition. The overall hydrogen bond dynamics at the supercritical condition was faster with respect to the aqueous azide ion solutions at the ambient condition.</p>


2019 ◽  
Author(s):  
Anwesa Karmakar

<p>A series of ab initio MD simulations has been carried out for aqueous azide (N<sub>3</sub><sup>-</sup>) ion solutions at three different densities and at supercritical condition (673 K) using Car-Parrinello molecular dynamics simulation. The time dependent trajectories at three different densities have been used to analyze the hydrogen bond dynamics, residence dynamics, dangling OD bond dynamics and spectral diffusion and underlying connections between them. The time dependent frequency of both the OD and NN stretching mode has been calculated using the time series analysis of the wavelet method. The population correlation function approach has been used to compute the hydrogen bond dynamics, dangling OD bond and residence dynamics of the Sc-water both inside and outside the solvation shell of the ion. The faster hydrogen bond dynamics has been observed in the vicinity of the azide ion, however the calculated OD stretching frequency is found to show red shift in the vicinity of the azide ion indicative to the formation of stronger ion-water hydrogen bond even at the supercritical condition. The overall hydrogen bond dynamics at the supercritical condition was faster with respect to the aqueous azide ion solutions at the ambient condition.</p>


2012 ◽  
Vol 85 (1) ◽  
pp. 27-40 ◽  
Author(s):  
Jyoti Roy Choudhuri ◽  
Vivek K. Yadav ◽  
Anwesa Karmakar ◽  
Bhabani S. Mallik ◽  
Amalendu Chandra

We present a first-principles simulation study of vibrational spectral diffusion and hydrogen-bond dynamics in solution of a fluoride ion in deuterated water. The present calculations are based on ab initio molecular dynamics simulation for trajectory generation and wavelet analysis for calculations of frequency fluctuations. The O–D bonds of deuterated water in the anion hydration shell are found to have lower stretching frequency than the bulk water. The dynamical calculations of vibrational spectral diffusion for hydration shell water molecules reveal three time scales: a short-time relaxation (~100 fs) corresponding to the dynamics of intact ion-water hydrogen bonds, a slower relaxation (~7.5 ps) corresponding to the lifetimes of fluoride ion-water hydrogen bonds, and an even longer time scale (~26 ps) associated with the escape dynamics of water from the anion hydration shell. However, the slowest time scale is not observed when the vibrational spectral diffusion is calculated over O–D bonds of all water molecules, including those in the bulk.


Physiology ◽  
2011 ◽  
Vol 26 (6) ◽  
pp. 381-392 ◽  
Author(s):  
Michael D. Fayer

In many situations, form biology to geology, water occurs not as the pure bulk liquid but rather in nanoscopic environments, in contact with interfaces, interacting with ionic species, and interacting with large organic molecules. In such situations, water does not behave in the same manner as it does in the pure bulk liquid. Water dynamics are fundamental to many processes such as protein folding and proton transport. Such processes depend on the dynamics of water's hydrogen bonding network. Here, the results of ultrafast infrared experiments are described that shed light on the influences of nanoconfinement, interfaces, ions, and organic molecules on water hydrogen bond dynamics.


2010 ◽  
Vol 114 (5) ◽  
pp. 2083-2089 ◽  
Author(s):  
Fabio Sterpone ◽  
Guillaume Stirnemann ◽  
James T. Hynes ◽  
Damien Laage

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