From elewars -A_T- alchemy.chem.utoronto.ca Thu Apr 3 11:40:11 1997 Received: from alchemy.chem.utoronto.ca for elewars %-% at %-% alchemy.chem.utoronto.ca by www.ccl.net (8.8.3/950822.1) id LAA29656; Thu, 3 Apr 1997 11:32:35 -0500 (EST) Received: (from elewars -x- at -x- localhost) by alchemy.chem.utoronto.ca (8.7.4/8.7.3) id LAA15225 for chemistry -x- at -x- www.ccl.net; Thu, 3 Apr 1997 11:32:32 -0500 (EST) Date: Thu, 3 Apr 1997 11:32:32 -0500 (EST) From: "E. Lewars" Message-Id: <199704031632.LAA15225 /at\alchemy.chem.utoronto.ca> To: chemistry: at :www.ccl.net Subject: HYDROGEN BONDS 1997 April 3 In response to a question by V. Divi about H-bonding computations on biomolecules: If you want trends rather than reliable absolute numbers, semiempirical or 3-21G ab initio calcs _may_ be adequate. PM3 may be better than AM1 for H-bonds. Also, look in the lit for applications of DFT to H-boding if you have access to DFT--its faster than comparable MP2 calcs. Some refs: H bonds relevant to biomolecules, semiemp and ab in: J Comp Chem 13 (1992) 1151 Modelling H-bonds and other weak bonds: Chem Rev 88 (1988) 871 6-31G* basis works well: J Org Chem 59 (1994) 803 Semiemp and ab in: J Org Chem 60 (1995) 1626 ====== E. Lewars ====================