Subject: MOPAC Thermo Calc's on PC's

From: [email-masked] (Jim Henshaw)
Date: Thu, 19 Jun 1997 09:01:11 +0100

Hi,
     
     I am a relatively new user of MOPAC, which I have been using on a 
     number of Pentium PC's (different operating systems, Windows 3.1, 95 
     etc.). I am trying to calculate thermodynamic properties of several 
     planar polyaromatic compounds, 10 to 30 C atoms, 10 to 30 H atoms. In 
     some of these systems a H, CH3 or CH3CH2 radical sits above the 
     aromatic plane (above a C atom), distorting the plane, as aromatic 
     carbon atoms change from sp2 to sp3 hybridisation. 
     
     I have several questions which MOPAC users may or may not be able to 
     help me with.
     
     1. Has any one carried out calculations on molecular systems similar 
     to those I have described ? 
     
     2. Does any one have any general hints in using the THERMO key word, 
     for example it seems to work better if I include the XYZ keyword and I 
     have optimised the geometry using PRECISE.
     
     3. For some of the molecules I am looking at, MOPAC version 7.0 
     performs the thermodynamic calculation OK, while version 6.0 does not? 
     What is the reason for this? I have not investigated this fully yet 
     using debugging keywords, but I intend too.
     
     4. Does anyone have any general hints/comments in relation to using 
     MOPAC on a PC ?
     
     5. Does any one know of a MOPAC version 7.0 that runs under Windows 95 
     ?

     Thanks to anybody who replies to any of my questions, and I will of 
     course summarise any answers I obtain for general consumption.

     Regards
     
     Jim 
     
     My e-mail address is [email-masked]