Tatsuhiko Ohto
September 24(Thu) - September 24(Thu), 2015
119 Seminar Room, College of Science(아산이학관)
Center for Molecular Spectroscopy and Dynamics
COLLOQUIUM | |
q SPEAKER
Professor Tatsuhiko Ohto
Graduate School of Engineering Science, Osaka University
q TITLE
On the hydration structure and dynamics near hydrophilic/hydrophobic group: A view from ab initio molecular dynamics simulation
q ABSTRACT
The structure and dynamics of interfacial water is of great importance in nature, since it is related to the wetting on the hydrophobic materials, stability of the aerosol in atmospheric chemistry, and designing and controlling the surface tension of the liquids. We perform ab initio MD (AIMD) simulations of the trimethylamine N-oxide (TMAO)-D2O solution to elucidate the effects of hydrophilic/hydrophobic part of TMAO on the reorientational dynamics of water molecules. In contrast with the previous results by experiment and force field MD simulation which claim slower reorientation motion of OH stretching near hydrophobic group compared with bulk water, we found very slow water dynamics near the hydrophilic group of TMAO. We attributed it to the strong directional hydrogen bond near the hydrophilic group through the sp3 orbital configuration. Furthermore, we developed an efficient algorithm based on the surface-specific velocity-velocity correlation function (ssVVCF) and calculated the SFG spectra at the water-air interface from the AIMD trajectory. The AIMD shows no 3100 cm-1 positive peak in contrast to the force field MD simulation, and is in good agreement with the very recent SFG measurement.
q DATE AND VENUE
Sep. 24, 2015 (4:00-5:00 p.m.) 아산이학관 119 (Seminar room)