The stress tensor of a molecular system: An exercise in statistical mechanics

2006 ◽  
Vol 125 (3) ◽  
pp. 034101 ◽  
Author(s):  
S. Morante ◽  
G. C. Rossi ◽  
M. Testa
Keyword(s):  
Statistical Mechanics ◽  
Stress Tensor ◽  
Molecular System

Statistical mechanics of inhomogeneous fluids

1982 ◽  
Vol 379 (1776) ◽  
pp. 231-246 ◽  
Keyword(s):  
Surface Tension ◽  
Free Energy ◽  
Angular Momentum ◽  
Statistical Mechanics ◽  
Stress Tensor ◽  
Pressure Difference ◽  
Strain Tensor ◽  
Pressure Tensor ◽  
Conservation Of Momentum ◽  
Statistical Mechanical

The nature of the microscopic stress tensor in an inhomogeneous fluid is discussed, with emphasis on the statistical mechanics of drops. Changes in free energy for isothermal deformations of a fluid are expressible as volume integrals of the stress tensor ‘times’ a strain tensor. A particular radial distortion of a drop leads to statistical mechanical expressions for the pressure difference across the surface of the drop. We find that the stress tensor is not uniquely defined by the microscopic laws embodying the conservation of momentum and angular momentum and that the am­biguity remains in the ensemble average, or pressure tensor, in regions of inhomogeneity. This leads to difficulties in defining statistical mechanical expressions for the surface tension of a drop.

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