Molecular dynamics study of polarity in room-temperature ionic liquids

被引:132
作者
Znamenskiy, V
Kobrak, MN
机构
[1] CUNY Brooklyn Coll, Dept Chem, Brooklyn, NY 11210 USA
[2] CUNY, Grad Ctr, Brooklyn, NY 11210 USA
关键词
D O I
10.1021/jp035891m
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
In this work, we use molecular dynamics simulation,to explore the physical principles governing the polarity of room-temperature ionic liquids. We use the calculated absorption spectrum of the solvatochromic dye molecule betaine-30 as a proxy for polarity and characterize the solute-solvent interactions responsible for the solvatochromic shift. We analyze specific solute-solvent interactions and discuss the complications posed by the proximity of counterions in solution. We also explore the question of competition between solute-solvent and sol vent-solvent interactions and find evidence supporting a recently proposed scheme for control of solvent polarity. Finally, we show that nonspecific electrostatic solute-solvent interactions are screened,by the ionic solvent, dictating that the thermodynamic properties of solvation are determined by local interactions. However, thermal fluctuations create transient long-ranged solute-solvent interactions that could be important for chemical kinetics.
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页码:1072 / 1079
页数:8
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