WATER CLUSTERS - CONTRIBUTIONS OF BINDING-ENERGY AND ENTROPY TO STABILITY

被引:158
作者
SHI, Z
FORD, JV
WEI, S
CASTLEMAN, AW
机构
[1] Department of Chemistry, Pennsylvania State University, University Park
关键词
D O I
10.1063/1.465678
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
The binding energies of water cluster cations are obtained by measuring decay fractions of metastable dissociation and employing Klots' model of evaporative dissociation. Their variation with degree of solvation shows the commonly observed decrease, followed by a slow rise in magnitude, which typifies the trend found for solvated cations. There is no observed abrupt change in the vicinity of the well-known magic number (H2O)21.H+ corresponding to (H2O)20.H3O+. Other data are used to deduce free energies for water clusters up to size n=28, allowing a determination of entropy changes with size. All of the thermochemical data, including prior literature values, are assessed in terms of calculations made using the liquid drop model and standard statistical mechanical equations. It is concluded that entropic rather than energetic effects give rise to the referred to magic number.
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页码:8009 / 8015
页数:7
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