TY - JOUR
T1 - Semiquantal molecular dynamics simulations of hydrogen-bond dynamics in liquid water using spherical Gaussian wave packets
AU - Ono, Junichi
AU - Hyeon-Deuk, Kim
AU - Ando, Koji
PY - 2013/2/5
Y1 - 2013/2/5
N2 - A semiquantal (SQ) molecular dynamics (MD) simulation method using spherical Gaussian wave packets (WPs) is applied to a microscopic analysis of hydrogen-bond (H-bond) exchange dynamics in liquid water. We focus on the molecular jump mechanism of H-bond reorientation dynamics proposed from a classical MD simulation by Laage and Hynes (Science 2006, 311, 832). As a notable quantum effect, broadenings of both the oxygen and hydrogen WPs of jumping water are observed associated with the H-bond switching events. Nonetheless, quantum effects on averaged trajectories of structural parameters measured with respect to the WP centers are rather minor. A 1/f fluctuation of local H-bond number is observed in both SQ and classical simulations. This is obtained straightforwardly from the real-time trajectories, in contrast with the originally found 1/f fluctuation (Sasai et al., J. Chem. Phys. 1992, 96, 3045) of the total potential energies collected at quenched inherent structures. The quantum effects are found to accelerate the relaxation of H-bond number fluctuation, which is reflected in the region near the lower bound of the 1/f behavior in the power spectra. New developments in the implementation of SQMD simulations including all atoms are also described.
AB - A semiquantal (SQ) molecular dynamics (MD) simulation method using spherical Gaussian wave packets (WPs) is applied to a microscopic analysis of hydrogen-bond (H-bond) exchange dynamics in liquid water. We focus on the molecular jump mechanism of H-bond reorientation dynamics proposed from a classical MD simulation by Laage and Hynes (Science 2006, 311, 832). As a notable quantum effect, broadenings of both the oxygen and hydrogen WPs of jumping water are observed associated with the H-bond switching events. Nonetheless, quantum effects on averaged trajectories of structural parameters measured with respect to the WP centers are rather minor. A 1/f fluctuation of local H-bond number is observed in both SQ and classical simulations. This is obtained straightforwardly from the real-time trajectories, in contrast with the originally found 1/f fluctuation (Sasai et al., J. Chem. Phys. 1992, 96, 3045) of the total potential energies collected at quenched inherent structures. The quantum effects are found to accelerate the relaxation of H-bond number fluctuation, which is reflected in the region near the lower bound of the 1/f behavior in the power spectra. New developments in the implementation of SQMD simulations including all atoms are also described.
KW - hydrogen bond dynamics
KW - molecular dynamics simulation
KW - quantum effects
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U2 - 10.1002/qua.24146
DO - 10.1002/qua.24146
M3 - Article
AN - SCOPUS:84872913741
VL - 113
SP - 356
EP - 365
JO - International Journal of Quantum Chemistry
JF - International Journal of Quantum Chemistry
SN - 0020-7608
IS - 3
ER -