From jstewart@fujitsu.fai.com Sun Jul 4 01:04:46 1993 Date: Sun, 4 Jul 93 08:04:46 PDT From: jstewart@fujitsu.fai.com (Dr. James Stewart) Message-Id: <9307041504.AA27992@fujitsu.fai.com> To: chemistry@ccl.net Subject: MOPAC 93 - reply regarding accuracy >From Dave Ewing, John Carroll University: > We cannot reproduce some of the published results on a couple of transition > states using MINDO/3 and MNDO. Our bond lengths agree but angles are off > by as much as 2 degrees and activation energies are off by nearly 1 Kcal/ > mol. The paper to which we are comparing was published in 1988. Are the > standard parameters slightly different now (we're using MOPAC 93) such that > these differences would be expected? The fundamental constants (e, h, c, etc.) in MOPAC 93 have been updated at the suggestion of Dr Yoshihisa Inoue of The Green Cross Corp, Japan, to conform with the CODATA standards. This will cause small changes in the results. The parameters in the methods have not been changed. See page 162 of the manual. Updating the fundamental constants was long overdue. As the new constants are accurate to about one part per million, I do not expect the next update of these constants to cause the results to change noticeably. Baker's EF routine has been improved by Dr Frank Jensen of Odense, Denmark, so that now a much higher precision can be achieved. See page 142 of the manual. Together these changes should account for the differences in the results obtained from MOPAC 93 and earlier results. James J. P. Stewart. From chemistry-request@ccl.net Sun Jul 4 18:29:22 1993 Date: Sat, 03 Jul 1993 13:10:50 -0400 (EDT) From: Gustavo Mercier Subject: HONDO and 5 canonical d orbitals To: chemistry@ccl.net Message-Id: Hi Netters! Does anybody know how to request that HONDO 7 use the 5 canonical d orbitals (i.e. dx2-y2 rather than dxx and dyy) instead of the default 6 cartesian d orbitals? Also, I have had some difficult interpreting a line from a paper on effective core potentials for transition metals? The paper gives the exponents and coefficients for the gaussian orbitals that form the pseudoorbitals when used as a minimal basis set. It then goes on to state: "Contracted ""double zeta" [2s2p2d] basis sets can be obtained by leaving the outermost function uncontracted and by contracting the remaining inner functions into a single function ACCORDING TO THE RATIOS (Ci) IN TABLES X-XII" The tables are the listing of the exponents and coefficients, Ci's, for the minimal basis set. Simply, how do you go from the minimal basis set to a double zeta as described above? What does the phrase ACCORDING TO THE RATIOS.. mean? Reference: P.J.Hay and W. R. Wadt J.Chem.Phys. 82(1) 270-283, 1985 "Ab initio effective core potentials for molecular calculations. Potentials for the transition metal atoms Sc to Hg" Any help would be welcomed Thanks gus mercie@cumc.cornell.edu --- Administrivia: This message is automatically appended by the mail exploder: CHEMISTRY@ccl.net --- everyone CHEMISTRY-REQUEST@ccl.net --- coordinator OSCPOST@ccl.net send help from chemistry Anon. ftp www.ccl.net CHEMISTRY-SEARCH@ccl.net --- search the archives, read help.search file first ---