Subject: calculating pKa's

From: "E. Lewars" <[email-masked]>
Date: Thu, 10 Mar 1994 17:32:28 -0500

Mahmood asks how to calculate pK's.  I don't know if there is a program that
will take the structure of an acid and spew out the pKa,
but pKa's can be estimated in at least two ways.  One can calculate
the energy of the acid and its conjugate base, or do an isodesmic reaction
calc and get the pK from the deltaE.  A simpler method is based on the 
correlation of maximum calc electrostatic potential with pKa.  
For examples, get hold of "Experiments in Computational Organic Chemistry"
by Hehre, Burke, Shusterman and Pietro (Wavefunction Inc, 1993;
(714)955-2120)).  See also Dewar and Dieter, JACS 1986 108 8075-86.
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