Since I came across you're note while installing Gaussian 94, I thought I'm take a moment to look up the references you, and I, are interested in With apologies to "et. al.":

J. A. Pople, et. al., "Gaussian-1 theory: A general procedure for prediction of molecular energies," J. Chem. Phys. 90, 5622 (1989).

L. A. Curtiss, et. al., "Gaussian-1 theory of molecular energies for second-row compounds," J. Chem. Phys. 93, 2537 (1990).

L.A. Curtiss, et. al., "Gaussian-2 theory for molecular energies for first- and second-row compounds," J. Chem. Phys. 94, 7221 (1991).

M.R.Nyden and G.A. Petersson, "Complete basis set correlation energies. I. The asymptotic convergence of pair natural orbital expansions," J. Chem. Phys. 75, 1843 (1981).

G.A.Petersson, et.al., "A complete basis set model chemistry. I. The total energies of closed-shell atoms and hydrides of the first-row atoms," J. Chem. Phys. 89, 2193 (1988)

G.A.Petersson and M.A. Al-Lahman, " A complete basis set model chemistry. II. Open-shell systems and the total energies of the first-row atoms," J. Chem. Phys. 94, 6081 (1991).

G.A. Petersson, et.al., "A complete basis set model chemistry. III. The complete basis set-quadratic configuration interaction family of methods," J. Chem. Phys. 94, 6091 (1991)

J.A. Montgomery, et.al., "A complete basis set model chemistry. IV. An improved atomic pair natural orbital method," J. Chem. Phys. 101, 5900 (1994).

J.W. Ochterski, et.al., "A complete basis set model chemistry. V. An extension to six or more heavy atoms," in preparation (1995).

You might consider getting a copy of the "Gaussian 94 User's Reference", $50, info@gaussian.com. It's a useful reference with 289 citations on the various methods and a much improved explanation of features, keywords, and job setup options and procedures.

By the way, a poster a member of T. Wipke's group presented at the ACS Anaheim meeting suggested that UHF/3-21G(*) may provide results of comparable quality to G1 and G2 at significantly lower "cost". I believe that a paper has been accepted for publication in the near future. _______________________________________________________________________ /