Subject: RE:thermochem in gaussian

From: "DR. LAWRENCE R. SCHMITZ" <[email-masked]>
Date: Fri, 11 Feb 1994 17:00:57 -0500 (EST)

Mike McAllister writes:
"Is there a reasonably straight forward way to get calculated
enthalpies from a gaussian frequency job??"

   My colleagues and I have been working on simple scheme to
calculate heats of formation from 6-31G* energies for several
years.  Our approach is to add an empirically determine set
of increments to the HF/6-31G* energy.  Once the increments
have been determined and the 6-31G* calculation done, the rest
of the calculation is simple (back of an envelope).  We have
published increment suitable for determining heats of formation
for a number of common functional groups as summarized below.

Alkenes. J. Comput. Chem., submitted.  (write to me if you
need these)

Alkyl Radicals. J. Phys. Org. Chem., 6, 551 (1993).

Thiols. Heteroatom Chem. 1992, 3, 69.

Acids and Esters. J. Comput. Chem.,  13, 838 (1992).

Aldehydes and Ketones. J. Phys. Org. Chem., 5, 225 (1992).

Alcohols and Ethers. J. Am. Chem. Soc., 114, 2880 (1992).

Alkanes and Aliphatic Amines. J. Phys. Org. Chem., 3, 732 (1990).

Larry

Larry Schmitz
Department of Chemistry
Marshall University
Huntington, WV 25755

[email-masked]