Calculation of solid-state13C NMR spectra of cellulose I α, I β and II using a semi-empirical approach and molecular dynamics

2000 ◽  
Vol 201 (15) ◽  
pp. 1930-1939 ◽  
Author(s):  
Frank-Thomas Koch ◽  
Wolfram Prieß ◽  
Raiker Witter ◽  
Ulrich Sternberg
Keyword(s):  
Molecular Dynamics ◽  
Nmr Spectra ◽  
Empirical Approach ◽  
Cellulose I ◽  
Semi Empirical

scholarly journals An Investigation into the Approximations Used in Wave Packet Molecular Dynamics for the Study of Warm Dense Matter

Plasma ◽  
2021 ◽  
Vol 4 (2) ◽  
pp. 294-308
Author(s):  
William A. Angermeier ◽  
Thomas G. White
Keyword(s):  
Molecular Dynamics ◽  
Wave Packet ◽  
Hydrogen Plasma ◽  
Valence Bond ◽  
Dense Matter ◽  
Basis Set ◽  
Warm Dense Matter ◽  
Scaling Parameters ◽  
Oppenheimer Approximation ◽  
Semi Empirical

Wave packet molecular dynamics (WPMD) has recently received a lot of attention as a computationally fast tool with which to study dynamical processes in warm dense matter beyond the Born–Oppenheimer approximation. These techniques, typically, employ many approximations to achieve computational efficiency while implementing semi-empirical scaling parameters to retain accuracy. We investigated three of the main approximations ubiquitous to WPMD: a restricted basis set, approximations to exchange, and the lack of correlation. We examined each of these approximations in regard to atomic and molecular hydrogen in addition to a dense hydrogen plasma. We found that the biggest improvement to WPMD comes from combining a two-Gaussian basis with a semi-empirical correction based on the valence-bond wave function. A single parameter scales this correction to match experimental pressures of dense hydrogen. Ultimately, we found that semi-empirical scaling parameters are necessary to correct for the main approximations in WPMD. However, reducing the scaling parameters for more ab-initio terms gives more accurate results and displays the underlying physics more readily.

Lipid Dynamics Studied by Calculation of 31P Solid-State NMR Spectra Using Ensembles from Molecular Dynamics Simulations

2014 ◽  
Vol 118 (19) ◽  
pp. 5119-5129 ◽  
Author(s):  
Sara K. Hansen ◽  
Mikkel Vestergaard ◽  
Lea Thøgersen ◽  
Birgit Schiøtt ◽  
Niels Chr. Nielsen ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Solid State ◽  
Molecular Dynamics Simulations ◽  
Solid State Nmr ◽  
Nmr Spectra ◽  
Lipid Dynamics ◽  
Dynamics Simulations
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