From owner-chemistry@ccl.net Wed Apr 1 08:38:00 2009 From: "Lydia Rhyman lyd_rhyman#%#hotmail.co.uk" To: CCL Subject: CCL: NBO interpretation Message-Id: <-38985-090401080149-23961-fVkajqfTBbsybBC4IKOkeQ]*[server.ccl.net> X-Original-From: "Lydia Rhyman" Date: Wed, 1 Apr 2009 08:01:45 -0400 Sent to CCL by: "Lydia Rhyman" [lyd_rhyman:_:hotmail.co.uk] Dear CCL Users In one of the NBO results, for a P-S bond in a molecule, I got sigma P-S = 0.612 (sp7.68)P + 0.791 (sp7.29)S I cannot understand the meaning of p power 7.68 and p power 7.29. Any help or suitable reference to understand NBO? Many thanks. L. Rhyman From owner-chemistry@ccl.net Wed Apr 1 11:14:01 2009 From: "Ramachandran Chelat rcchelat{:}rediffmail.com" To: CCL Subject: CCL: Coordinates for Structure I and Structure II hydrates Message-Id: <-38986-090401110015-15989-YFhVYmupf9miDiQXlN/oKA*server.ccl.net> X-Original-From: "Ramachandran Chelat" Date: Wed, 1 Apr 2009 11:00:09 -0400 Sent to CCL by: "Ramachandran Chelat" [rcchelat**rediffmail.com] Dear CCL friends, I am looking for the coordinates for Structure I and Structure II in which gas hydrates are forming. Can you please help me to get coordinates or references of the same for a unit cell of these structures Thanks in advance Ramachandran From owner-chemistry@ccl.net Wed Apr 1 12:32:01 2009 From: "Close, David M. CLOSED ~ mail.etsu.edu" To: CCL Subject: CCL:G: QCISD??? Message-Id: <-38987-090401123053-17622-Xw92UGia7mZ4AtJGa7vVuA|a|server.ccl.net> X-Original-From: "Close, David M." Content-class: urn:content-classes:message Content-Type: multipart/alternative; boundary="----_=_NextPart_001_01C9B2E7.2CBFAEB4" Date: Wed, 1 Apr 2009 12:30:36 -0400 MIME-Version: 1.0 Sent to CCL by: "Close, David M." [CLOSED++mail.etsu.edu] This is a multi-part message in MIME format. ------_=_NextPart_001_01C9B2E7.2CBFAEB4 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable To CCL: I have several questions about CIS CISD and QCISD. At first I had problems with several calculations that exceeded the preset (50) number of iterations allowed. The manual says one can set MaxCyl=3D and = Conver=3D. But this didn't work with inputs values on the Gaussian command line (#). However I was able to work around this with Iop (9/6=3D-1). But = in fooling with this I realized that I don't understand want the program is trying to do. If the first iteration succeeds, the program outputs the "Dominant Configurations" This is in a small table with headings Spin Case and the letters I J A B. I have no idea what the heading are, and what the entries represent. If one is using QCISD, the this if followed by another set of iterations called "Z-amplitude Iterations". I have no idea what these calculations represent. I want to understand what the program is doing so that I can make some rather long calculations more tractable. Next I am interested in QCISD(T). I am working with open-shell systems, and the manual says the program cannot use the DENSITY keyword for these type of calculations. Does anyone know of other code that can handle a QCISD(T) calculation where one can recover the Density calculated with the CI rather than the SCF values? Regards, Dave Close. ------_=_NextPart_001_01C9B2E7.2CBFAEB4 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

  To CCL:

  I have several questions about CIS CISD and QCISD.  At first I had problems with several calculations that = exceeded the preset (50) number of iterations allowed.  The manual says one = can set MaxCyl=3D and Conver=3D.  But this didn’t work with inputs = values on the Gaussian command line (#).  However I was able to work around this = with Iop (9/6=3D-1).  But in fooling with this I realized that I = don’t understand want the program is trying to do.  If the first = iteration succeeds, the program outputs the “Dominant = Configurations”  This is in a small table with headings   Spin Case and the = letters I J A B.  I have no idea what the heading are, and what the entries represent.  If one is using QCISD, the this if followed by another = set of iterations called “Z-amplitude Iterations”.  I have no = idea what these calculations represent.

  I want to understand what the program is = doing so that I can make some rather long calculations more = tractable.

  Next I am interested in QCISD(T).  I am = working with open-shell systems, and the manual says the program cannot use the = DENSITY keyword for these type of calculations.  Does anyone know of other = code that can handle a QCISD(T) calculation where one can recover the Density = calculated with the CI rather than the SCF values?

  Regards, Dave Close.

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