scholarly journals Comparative studies of IR spectra of deprotonated serine with classical and thermostated ring polymer molecular dynamics simulations

2021 ◽  
Vol 8 (5) ◽  
pp. 054101
Author(s):  
V. S. Sandeep Inakollu ◽  
Haibo Yu
Keyword(s):  
Molecular Dynamics ◽  
Ir Spectra ◽  
Molecular Dynamics Simulations ◽  
Comparative Studies ◽  
Ring Polymer ◽  
Ring Polymer Molecular Dynamics ◽  
Dynamics Simulations

Photoexcited Ag ejection from a low-temperature He cluster: a simulation study by nonadiabatic Ehrenfest ring-polymer molecular dynamics

2017 ◽  
Vol 19 (21) ◽  
pp. 13798-13806 ◽  
Author(s):  
Yusuke Seki ◽  
Toshiyuki Takayanagi ◽  
Motoyuki Shiga
Keyword(s):  
Molecular Dynamics ◽  
Low Temperature ◽  
Molecular Dynamics Simulations ◽  
Simulation Study ◽  
Ring Polymer ◽  
Cluster A ◽  
Ring Polymer Molecular Dynamics ◽  
Dynamics Simulations

Nonadiabatic ring-polymer molecular dynamics simulations were performed to understand the photoexcitation dynamics of a low-temperature Ag·He500 cluster.

Nuclear quantum effects in the direct ionization process of pure helium clusters: path-integral and ring-polymer molecular dynamics simulations on the diatomics-in-molecule potential energy surfaces

2018 ◽  
Vol 20 (41) ◽  
pp. 26489-26499 ◽  
Author(s):  
Kento Suzuki ◽  
Takaaki Miyazaki ◽  
Toshiyuki Takayanagi ◽  
Motoyuki Shiga
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Path Integral ◽  
Potential Energy Surfaces ◽  
Direct Ionization ◽  
Helium Clusters ◽  
Pure Helium ◽  
Ring Polymer ◽  
Ring Polymer Molecular Dynamics ◽  
Dynamics Simulations

The ionization dynamics of pure Hen clusters has been theoretically studied using path-integral and ring-polymer molecular dynamics simulations.

scholarly journals Theoretical Investigations on the Reactivity of Methylidyne Radical toward 2,3,7,8-Tetrachlorodibenzo-p-Dioxin: A DFT and Molecular Dynamics Study

Molecules ◽  
2018 ◽  
Vol 23 (10) ◽  
pp. 2685 ◽  
Author(s):  
Weihua Wang ◽  
Wenling Feng ◽  
Wenliang Wang ◽  
Ping Li
Keyword(s):  
Molecular Dynamics ◽  
Ir Spectra ◽  
Ab Initio ◽  
Molecular Dynamics Simulations ◽  
Hyperfine Coupling ◽  
Coupling Constants ◽  
Ab Initio Molecular Dynamics ◽  
Hyperfine Coupling Constants ◽  
Dynamics Simulations ◽  
Ch Radical

To explore the potential reactivity of the methylidyne radical (CH) toward 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), the reaction mechanism between them has been systematically investigated employing the density functional theory (DFT) and ab initio molecular dynamics simulations. The relevant thermodynamic and kinetic parameters in the possible reaction pathways have been discussed as well as the IR spectra and hyperfine coupling constants (hfcc’s) of the major products. Different from the reaction of the CH radical with 2,3,7,8-tetrachlorodibenzofuran, CH radical can attack all the C-C bonds of TCDD to form an initial intermediate barrierlessly via the cycloaddition mechanism. After then, the introduced C-H bond can be further inserted into the C-C bond of TCDD, resulting in the formation of a seven-membered ring structure. The whole reactions are favorable thermodynamically and kinetically. Moreover, the major products have been verified by ab initio molecular dynamics simulations. The distinct IR spectra and hyperfine coupling constants of the major products can provide some help for their experimental detection and identification. In addition, the reactivity of the CH radical toward the F- and Br-substituted TCDDs has also been investigated. Hopefully, the present findings can provide new insights into the reactivity of the CH radical in the transformation of TCDD-like dioxins.

scholarly journals Investigating Tunneling Controlled Chemical Reactions Through Ab-Initio Ring Polymer Molecular Dynamics

2021 ◽  
Author(s):  
Xinyang Li ◽  
Pengfei Huo
Keyword(s):  
Molecular Dynamics ◽  
Ab Initio ◽  
Chemical Reaction ◽  
Quantum Tunneling ◽  
Quantum Dynamics ◽  
Density Functional ◽  
Molecular System ◽  
Ring Polymer ◽  
Ring Polymer Molecular Dynamics ◽  
Dynamics Simulations

<div>We use the ab-initio ring polymer molecular dynamics (RPMD) approach to investigate tunneling controlled reactions in methylhydroxycarbene. Nuclear tunneling effects enable molecules to overcome the barriers which can not be overcome classically. Under low-temperature conditions, intrinsic quantum tunneling effects canfacilitate the chemical reaction in a pathway that is neither favored thermodynamically nor kinetically. This</div><div>behavior is referred to as the tunneling controlled chemical reaction and regarded as the third paradigm of chemical</div><div>reaction controls. In this work, we use the ab-initio RPMD approach to incorporate the tunneling effects in our quantum dynamics simulations. The reaction kinetics of two competitive reaction pathways at various temperatures are investigated with the Kohn-Sham density functional theory (KS-DFT) on-the-fly molecular dynamics simulations and the ring polymer quantization of the nuclei. The reaction rate constants obtained here agree extremely well with the experimentally measured rates. We demonstrate the feasibility of using ab-initio RPMD rate calculations in a realistic molecular system, and provide an interesting and important example for future investigations on reaction mechanisms dominated by quantum tunneling effects.</div>

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