From owner-chemistry@ccl.net Mon Jan 30 10:30:01 2006
From: "John McKelvey jmmckel~!~attglobal.net" <owner-chemistry+/-server.ccl.net>
To: CCL
Subject: CCL: MD software question.
Message-Id: <-30699-060130090027-7772-FA0b0RqRbeMADKOVT1Kp7w+/-server.ccl.net>
X-Original-From: John McKelvey <jmmckel,+,attglobal.net>
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Date: Mon, 30 Jan 2006 08:54:59 -0500
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Sent to CCL by: John McKelvey [jmmckel++attglobal.net]
Andrew,

You asked me some time ago about choice of basis sets for correlation 
calculations, and I have not answered.  I do not have a good answer.  I 
suppose there are the obvious things you already are aware of.. 
6-31G[d], 6311[d,p]... etc, the SVxP[d,p,f..] from T'mole, 
couple-cluster basis sets, augmented basis sets, etc..  I am just not up 
to speed on this.  You might lood into work of the T'mole people, among 
others.

BTW, if you want a very good, free QM package take a look at ORCA, by 
Frank Neese.

Best regards,

John McKelvey


Andrew Fant fant(~)pobox.com wrote:

>Sent to CCL by: Andrew Fant [fant]_[pobox.com]
>Mrcel and James both made good points that I won't bother duplicating here.  One 
>other thing to bear in mind is that while the math(s) involved in MD is 
>relatively straightforward, doing it efficiently usually isn't.  Even in 
>single-threaded code, there are a whole constellation of 
>tricks/shortcuts/advanced techniques that can make things go much faster (an 
>order of magnitude or more) compared to what a naive undergrad might achieve 
>left to their own devices.  And when you get into parallel processing, it 
>becomes even more hairy.
>
>Andy
>
>  
>