TY - JOUR
T1 - Orientational Disorder of Alcohol Molecules at Their Solution Surfaces in Low Concentration Range
T2 - A Molecular Dynamics Simulation Study
AU - Hirose, Mayu
AU - Ishiyama, Tatsuya
N1 - Publisher Copyright:
© 2024 American Chemical Society.
PY - 2024/11/21
Y1 - 2024/11/21
N2 - Molecular dynamics (MD) simulations of short-chain alcohols (methanol, ethanol, and 1-propanol) in solution were carried out to examine the orientational disordering (randomizing) of alcohol molecules at the surface under diluted conditions. Recent vibrational sum frequency generation (VSFG) spectroscopy, combined with photoelectron spectroscopy, has successfully measured the disordering structure at low concentrations. The present MD simulations accurately reproduce this observation for the first time. To ensure reliable results through MD simulations, several widely used force field models for water and alcohol, including polarizable models, were examined. This examination involved a comparison of structural and thermodynamic quantities, such as surface density times orientation and surface excess concentration, which were obtained through surface-specific measurements like VSFG spectroscopy and surface tension measurements. It is found that the width of the density profile for alcohol molecules at the surface, along the surface normal, increases as the concentration decreases in the diluted condition, which is consistent with the results obtained from the previous neutron and X-ray grazing incidence reflection experiments. A molecular mechanism explaining the disordering of alcohol molecules with decreasing concentration is also discussed.
AB - Molecular dynamics (MD) simulations of short-chain alcohols (methanol, ethanol, and 1-propanol) in solution were carried out to examine the orientational disordering (randomizing) of alcohol molecules at the surface under diluted conditions. Recent vibrational sum frequency generation (VSFG) spectroscopy, combined with photoelectron spectroscopy, has successfully measured the disordering structure at low concentrations. The present MD simulations accurately reproduce this observation for the first time. To ensure reliable results through MD simulations, several widely used force field models for water and alcohol, including polarizable models, were examined. This examination involved a comparison of structural and thermodynamic quantities, such as surface density times orientation and surface excess concentration, which were obtained through surface-specific measurements like VSFG spectroscopy and surface tension measurements. It is found that the width of the density profile for alcohol molecules at the surface, along the surface normal, increases as the concentration decreases in the diluted condition, which is consistent with the results obtained from the previous neutron and X-ray grazing incidence reflection experiments. A molecular mechanism explaining the disordering of alcohol molecules with decreasing concentration is also discussed.
UR - http://www.scopus.com/inward/record.url?scp=85208697366&partnerID=8YFLogxK
U2 - 10.1021/acs.jpcb.4c04611
DO - 10.1021/acs.jpcb.4c04611
M3 - 学術論文
C2 - 39505829
AN - SCOPUS:85208697366
SN - 1520-6106
VL - 128
SP - 11450
EP - 11459
JO - Journal of Physical Chemistry B
JF - Journal of Physical Chemistry B
IS - 46
ER -