TY - JOUR
T1 - Hydrogenic Stretch Spectroscopy of Glycine-Water Complexes
T2 - Anharmonic Ab Initio Classical Separable Potential Calculations
AU - Sagiv, Lior
AU - Hirshberg, Barak
AU - Gerber, R. Benny
N1 - Publisher Copyright:
Copyright © 2019 American Chemical Society.
PY - 2019/10/3
Y1 - 2019/10/3
N2 - The anharmonic frequencies of O-H, C-H, and N-H stretching modes of hydrogen-bonded glycine-H2O complexes are calculated using ab initio classical separable potential approximation. In this approach, ab initio molecular dynamic simulations are used to determine an effective classical potential for each of the normal modes of the system. The frequencies are calculated by solving the time-independent Schrödinger equation for each mode using time-averaged potentials. Three complex structures are studied, which differ in the location of the water molecule on the amino acid. Significant differences are found between the spectra of the three structures, and signatures of individual complexes are established. It is demonstrated that anharmonic effects are essential in the discrimination between different structures, while frequency differences at the harmonic level are much smaller. Intensities are also computed and found to carry information on differences between structures, but the role of anharmonicity in this is small.
AB - The anharmonic frequencies of O-H, C-H, and N-H stretching modes of hydrogen-bonded glycine-H2O complexes are calculated using ab initio classical separable potential approximation. In this approach, ab initio molecular dynamic simulations are used to determine an effective classical potential for each of the normal modes of the system. The frequencies are calculated by solving the time-independent Schrödinger equation for each mode using time-averaged potentials. Three complex structures are studied, which differ in the location of the water molecule on the amino acid. Significant differences are found between the spectra of the three structures, and signatures of individual complexes are established. It is demonstrated that anharmonic effects are essential in the discrimination between different structures, while frequency differences at the harmonic level are much smaller. Intensities are also computed and found to carry information on differences between structures, but the role of anharmonicity in this is small.
UR - http://www.scopus.com/inward/record.url?scp=85072905410&partnerID=8YFLogxK
U2 - 10.1021/acs.jpca.9b05378
DO - 10.1021/acs.jpca.9b05378
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C2 - 31538481
AN - SCOPUS:85072905410
SN - 1089-5639
VL - 123
SP - 8377
EP - 8384
JO - Journal of Physical Chemistry A
JF - Journal of Physical Chemistry A
IS - 39
ER -