THE ROLE OF SOLVENT STRUCTURE IN PERTURBATION-METHODS APPLIED TO THE DISSOLUTION OF AN APOLAR SOLUTE IN WATER

In view of recent experimental and simulation studies which show that solvent reorientation does not play a significant role in the dissolut ion of small apolar solutes in water, the performance of first order p erturbation theories (FOPT) has been reassessed. A contribution which cannot be obtained from classical FOPT is the many-body effect of the instantaneous solvent electric field which induces a dipole on the apo lar solute and contributes an attractive term. The average square elec tric field was determined by molecular dynamics for solutes of differe nt size and its effect upon the solute's chemical potential was calcul ated from it with an appropriate extension of the test-particle method . The contribution of this term to the thermodynamic quantities of dis solution is discussed.