Subject: Re: CCL:HyperChem

From: "Antti Poso" <[email-masked]>
Date: Wed, 1 Jun 1994 09:01:27 EST5EDT

> Date:          Tue, 31 May 1994 18:13:56 +0200 (IST)
> From:          "Schriver,M;Chemistry;" <[email-masked]>
> Subject:       CCL:HyperChem 
> To:            [email-masked]
> Cc:            [email-masked]

> 
> Hi,
> 
> I've been lurking here recently and was hesitant to post but Rafael
> Najmanovich posted a request yesterday that struck home. Last year I
> wanted a software package that would 1) give publishable semi-empirical
> calculations on small molecules 2) be easy to use and 3) generate
> high quality graphics output of molecules and orbitals. 

<stuff deleted>

So far I agree

> To make a long story short a couple of chemists more familiar with theoret-
> ical chemistry that I recently talked to were so negative on the program I am
> seriously reconsidering publishing anything I get from the package even if
> it confirms my experimental results. They said that the parameterisation
> of the package was so poor that the only reliable results would be on the
> exact same molecules that HyperChem used to create the parameter files.
> Since I am looking at S and P in small hetercycles I was warned very strongly
> against using HyperChem in AM1 or PM3 calculations.
> 
> They then proceded to tell me that the only reliable results would come 
> from programs that have names that encompass half the alphabet and most 
> of the alternate characters on the keyboard. Leaving me with the idea 
> that these calculations should be left to the professionals

WHY, ALLWAYS? Of course there are difficult cases, but still..

>. Oh well.
> 
> Before I throw away my copy of HyperChem could this list please address
> this issue? Where are semi-empirical calculations reliable? Is there a 
> difference between AM1 in HyperChem and AM1 in the original manuscripts?

Well, those chemist more familiar with theoretical chemistry are 
likely to be the the shareholders of some other softwarecompany :-)
My experience with HyperChem are good (not excellent), but so far all 
results from AM1 and PM3 calculations with HyperChem have been 
equal to the results from MOPAC or AMPAC (well, there are some 
differences, if you look the last digit :-)). To be honest, there is 
one article coming out where we used HyperChem. (Sulfur analogues of 
plychlorinated dibenzo-p-dioxins, ....., Kopponen, Sinkkkonen, Poso, 
Gynther, Kärenlampi; Enviromental Toxicology and Chemistry, Vol 13, 
No, 9, scheduled for publication on 8/24/94.) 

> If Rafael gets any personal answers could he please post them here?
> 			Thanx in advance
> 							Mel
> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> + M.J. Schriver, Assist. Prof.,     + Ph.  (709) 737-8744              +
> + Memorial University of NFLD       + Fax  (709) 737-3702              +
> + St. John's, NFLD, Canada, A1B 3X7 + eml  [email-masked]   +

Antti Poso   [email-masked]  phone: +358-(9)71-162462             
Department of Pharmaceutical Chemistry   fax: -162456
University of Kuopio      
Finland                  
                    pro fide