CCL:G: "MP2" and "Density" keywords

 Sent to CCL by: [willsd[A]appstate.edu]
 Radek:
 Yes you do need to use density=current to have aim2000 analyze the MP2
 electronic structure. Without this keyword the orbitals printed to the .wfn file
 will be SCF orbitals that do not reflect the correlation energy you are using
 MP2 to account for.  You can tell if you have done this correcty: with SCF
 results the orbital occupations will (for your closed shell system) be either 2
 or 0.  The MP2 results will have occupations that will be fractional.
 I do not think you need density=current for B3LYP, but I am not 100% certain.
 For B3LYP the SCF results should be the solution of the KS equations, with a bit
 of HF solution as well.
 Steve Williams
 ----- Original Message -----
 > From: "Radoslaw Kaminski rkaminski.rk(!)gmail.com"
 <owner-chemistry-*-ccl.net>
 Date: Saturday, December 6, 2008 6:35 am
 Subject: CCL:G: "MP2" and "Density" keywords
 To: "Williams, Steve " <willsd-*-conrad.appstate.edu>
 >
 > Sent to CCL by: "Radoslaw  Kaminski" [rkaminski.rk]-[gmail.com]
 > Hi Everyone,
 >
 > I'm doing (or maybe trying to do...) some calculations for simple
 > metal complexes using the Gaussian 03 (E01 version). I applied the
 > MP2 method for this and quite a big (I think) base to do that. I
 > want to analyse the electron density in the AIM2000 program so I
 > have to put the appropriate keyword in the route section, like this
 > (I have the optimized geometries):
 >
 > # MP2/AUG-cc-pVTZ Output=WFN
 >
 > And so, there are my questions:
 >
 > 1) Do I have to use the Density=Current keyword? I truly don't
 > understand how it works. I have read something in the Internet
 > about it and also previous CCL posts, but still I'm not sure.
 >
 > 2) In that cases do we have to use this Density=Current keyword? I
 > know that, for sure, in the case of using the B3LYP method, but
 > what else?
 >
 > Some details about my system? A few atoms like H, N, B, Al, Ga,
 > complexes are uncharged and in a singlet state (the shell is closed).
 >
 > Thanks for help and all the best.
 >
 > Radek Kaminski
 >
 >
 >
 > -= This is automatically added to each message by the mailing
 > script =-
 > To recover the email address of the author of the message, please
 > changethe strange characters on the top line to the -*- sign. You can
 > also> Conferences:
 > http://server.ccl.net/chemistry/announcements/conferences/
 > Search Messages: http://www.ccl.net/htdig  (login: ccl, Password:
 > search)>
 >
 >