From elewars@alchemy.chem.utoronto.ca Mon Dec 25 14:36:18 1995 Received: from alchemy.chem.utoronto.ca for elewars@alchemy.chem.utoronto.ca by www.ccl.net (8.6.10/950822.1) id OAA15504; Mon, 25 Dec 1995 14:25:18 -0500 Received: (from elewars@localhost) by alchemy.chem.utoronto.ca (8.7.1/8.7.1) id OAA12368 for chemistry@www.ccl.net; Mon, 25 Dec 1995 14:25:18 -0500 (EST) Date: Mon, 25 Dec 1995 14:25:18 -0500 (EST) From: "E. Lewars" Message-Id: <199512251925.OAA12368@alchemy.chem.utoronto.ca> To: chemistry@www.ccl.net Subject: STRANGE PROBLEM WITH FREQS 1995 Dec 25 MERRY CHRISTMAS AND A HAPPY 1996! Hello, I have an interesting problem connected with Spartan. I did an opt/freq on the unusual molecule Me Me \ / Me /C\ Me C------ C \ // \ \ / | \ / | \ /-/------\-\ / | C | C(C-Me)4 Tetramethylpyramidane [/__________\] | / \ | / \ C--------C NOTE: pyramidane, C(CH)4, is / \ / \ a relative minimum (no Me Me Me Me imaginary freqs) at the HF/6-31G*, MP2/6-31G* and C4v MP2/6-31++G** levels. (The HF/6-31G* geom is given in the file below) The HF/6-31G* opt proceeded normally (E=-347.628 348), but the freqs are absurd: -68748.51 E -68748.51 E -22116.22 A1 -11996.37 B1 (followed by sensible +ve freqs 151.29 B2 151.88 A2 etc.) ZPE = 566.02 kcal/mol Finding this hard to accept, I used the Spartan HF/6-31G* geom as input for a Gaussian 92 HF/6-31G* opt/freq. The Gaussian opt (which needed only one opt cycle) gave the same E as Spartan (-347.628 348 6) but the freqs and ZPE were quite different (the E from the freq job was also -347.628 348): +163.42 E +163.42 E +164.03 A2 +164.64 B1 +182.69 B2 etc ZPE = 120.42 kcal/mol Has anyone any idea why the two programs gave such different results? I presume that the "huge negative" freqs are simply wrong, and the Gaussian freqs are correct; the parent compound C5H4, and other substituted pyramidanes, gave normal freqs. Thanks for any suggestions. Errol Lewars -------------------------- This is the Spartan HF/6-31G* geom (=G92 HF/6-31G* geom) and connectivity: C OPT HF DIRECT 6-31G* DAMP=.75 HESS=ARCH GUESS=READ FREQ maxcycle=200 Input: C4v 3-21G 0 1 ;6 2.504069003 0.000000000 0.057343366 6 0.000000000 1.017992876 0.196489929 6 1.017992876 0.000000000 0.196489929 6 -1.017992876 0.000000000 0.196489929 6 0.000000000 -1.017992876 0.196489929 6 0.000000000 0.000000000 -1.055200740 6 0.000000000 -2.504069003 0.057343366 6 0.000000000 2.504069003 0.057343366 6 -2.504069003 0.000000000 0.057343366 1 0.000000000 -2.982679331 1.031452811 1 0.876613239 -2.837789716 -0.485825815 1 -0.876613239 -2.837789716 -0.485825815 1 -2.837789716 -0.876613239 -0.485825815 1 -2.837789716 0.876613239 -0.485825815 1 -2.982679331 0.000000000 1.031452811 1 0.876613239 2.837789716 -0.485825815 1 0.000000000 2.982679331 1.031452811 1 -0.876613239 2.837789716 -0.485825815 1 2.982679331 0.000000000 1.031452811 1 2.837789716 0.876613239 -0.485825815 1 2.837789716 -0.876613239 -0.485825815 ENDCART FROZEN ENDFROZEN PI ENDPI PAIRING ENDPAIR HESSIAN 1 1 1 1 1 1 1 1 1 13 13 13 13 13 13 13 13 13 13 13 13 6 2 1 2 8 1 2 3 1 2 4 1 3 1 1 3 6 1 3 5 1 4 9 1 6 4 1 4 5 1 6 5 1 5 7 1 7 10 1 7 11 1 7 12 1 9 13 1 9 14 1 9 15 1 8 16 1 8 17 1 8 18 1 1 19 1 1 20 1 1 21 1 ENDHESS From P8946019@vmsuser.acsu.unsw.EDU.AU Mon Dec 25 21:21:24 1995 Received: from vmsuser.acsu.unsw.EDU.AU for P8946019@vmsuser.acsu.unsw.EDU.AU by www.ccl.net (8.6.10/950822.1) id VAA18214; Mon, 25 Dec 1995 21:07:04 -0500 From: Received: from vmsuser.acsu.unsw.EDU.AU by vmsuser.acsu.unsw.EDU.AU (PMDF V4.3-13 #6323) id <01HZ9IV49EQU8WX9AY@vmsuser.acsu.unsw.EDU.AU>; Tue, 26 Dec 1995 13:11:46 +1000 Date: Tue, 26 Dec 1995 13:11:46 +1000 Subject: STO summary To: chemistry@www.ccl.net Message-id: <01HZ9IV49EQW8WX9AY@vmsuser.acsu.unsw.EDU.AU> X-VMS-To: IN%"chemistry@www.ccl.net" MIME-version: 1.0 Content-type: TEXT/PLAIN; CHARSET=US-ASCII Content-transfer-encoding: 7BIT Dear Computational Chemist I recently posted a message about the use of STOs in ab initio calcs. Thanks to everyone who responded. I received 7 replies, most of them referred me to a program called ADF- short for Amsterdam Density Functional. Hugh