Efficient Computation of Difference Vibrational Spectra in Isothermal-Isobaric Ensemble.
Tatsuya Joutsuka1, Akihiro Morita1,2
1Department of Chemistry, Graduate School of Science, Tohoku University , Sendai 980-8578, Japan.
The Journal of Physical Chemistry. B
|October 11, 2016
Summary
We developed a computationally efficient algorithm for calculating difference spectra, avoiding direct subtraction. This method accurately captures spectral changes, even tiny ones, with significant speed improvements for molecular dynamics simulations.
Area of Science:
- Computational Chemistry
- Spectroscopy
- Molecular Dynamics
Background:
- Difference spectroscopy enhances selectivity but requires computationally intensive calculations.
- Direct subtraction of spectra from molecular dynamics is often too demanding for tiny spectral differences.
Purpose of the Study:
- To develop an efficient computational algorithm for calculating difference spectra without subtraction.
- To extend the theoretical method to the isothermal-isobaric (NPT) ensemble.
- To analyze pressure dependence of spectra and elucidate anomalous behavior.
Main Methods:
- Proposed an efficient computational algorithm for difference spectra calculation.
- Extended the theoretical method to the isothermal-isobaric (NPT) ensemble.
- Applied the method to vibrational spectra of liquid water under varying pressure.
Main Results:
- The new method yields accurate difference spectra in the NPT ensemble.
- Achieved computational efficiency several orders of magnitude greater than straightforward subtraction.
- Successfully reproduced tiny difference spectra due to pressure changes in liquid water.
Conclusions:
- The developed method offers remarkable computational efficiency for difference spectra analysis.
- The theory accurately captures pressure-dependent spectral changes in liquid water.
- Elucidated anomalous pressure dependence in relation to other liquid water properties.
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