TY - JOUR
T1 - Intrinsic structure and dynamics of the water/nitrobenzene interface
AU - Jorge, Miguel
AU - Cordeiro, M. Natalia D. S.
N1 - This document is the unedited Author’s version of a Submitted Work that was subsequently accepted for publication in Journal of Physical Chemistry C, copyright © American Chemical Society after peer review. To access the final edited and published work see http://pubs.acs.org/doi/abs/10.1021/jp076178q.
PY - 2007/11/29
Y1 - 2007/11/29
N2 - In this paper we present results of a detailed and systematic molecular dynamics study of the water/nitrobenzene interface. Using a simple procedure to eliminate fluctuations of the interface position, we are able to obtain true intrinsic profiles for several properties (density, hydrogen bonds, molecular orientation, etc.) in the direction perpendicular to the interfacial plane. Our results show that both water and organic inter-facial molecules form a tightly packed layer oriented parallel to the interface, with reduced mobility in the perpendicular direction. Beyond this layer, water quickly restores its bulk structure, while nitrobenzene exhibits structural anisotropies that extend further into the bulk region: Water molecules that protrude farthest into the organic phase point one hydrogen atom in the direction perpendicular to the interface, forming a hydrogen bond with a nitrobenzene oxygen. By fitting both the global and the intrinsic density profiles, we obtain estimates for the total and intrinsic interface widths, respectively. These are combined with capillary wave theory to produce a self-consistent method for the calculation of the inter-facial tension. Values calculated using this method are in very good agreement with direct calculations from the components of the pressure tensor.
AB - In this paper we present results of a detailed and systematic molecular dynamics study of the water/nitrobenzene interface. Using a simple procedure to eliminate fluctuations of the interface position, we are able to obtain true intrinsic profiles for several properties (density, hydrogen bonds, molecular orientation, etc.) in the direction perpendicular to the interfacial plane. Our results show that both water and organic inter-facial molecules form a tightly packed layer oriented parallel to the interface, with reduced mobility in the perpendicular direction. Beyond this layer, water quickly restores its bulk structure, while nitrobenzene exhibits structural anisotropies that extend further into the bulk region: Water molecules that protrude farthest into the organic phase point one hydrogen atom in the direction perpendicular to the interface, forming a hydrogen bond with a nitrobenzene oxygen. By fitting both the global and the intrinsic density profiles, we obtain estimates for the total and intrinsic interface widths, respectively. These are combined with capillary wave theory to produce a self-consistent method for the calculation of the inter-facial tension. Values calculated using this method are in very good agreement with direct calculations from the components of the pressure tensor.
KW - intrinsic structure
KW - dynamics
KW - water/nitrobenzene interface
UR - http://pubs.acs.org/journal/jpccck
U2 - 10.1021/jp076178q
DO - 10.1021/jp076178q
M3 - Article
SN - 1932-7447
VL - 111
SP - 17612
EP - 17626
JO - Journal of Physical Chemistry C
JF - Journal of Physical Chemistry C
IS - 47
ER -