Re: CCL:Defining orbitals



 
Using valence bond (VB) theory you can define anything you want (any state and any wavefunction). It is not implemented in gaussian, but in games-uk e.g. it is.
 Shobe, David wrote:
 
Yes, but...I think he wants to study what would more correctly be called a particular state of Li anion triplet. I don't remember how Gaussian treats the degeneracy of the three p orbitals. If Gaussian just arbitrarily picks one of the three p orbitals, no special manipulation is needed; but if the HOMO is a mixture of px, py, and pz it's a different story...
 --David Shobe, Ph.D., M.L.S.
 S|d-Chemie, Inc.
 phone (502) 634-7409
 fax (502) 634-7724
 Don't bother flaming me: I'm behind a firewall.
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*From:* Computational Chemistry List [mailto:chemistry-request:at:ccl.net] *On Behalf Of *Wayne Steinmetz
 *Sent:* Friday, June 10, 2005 4:46 PM
 *To:* chemistry:at:ccl.net
 *Subject:* CCL:Defining orbitals
 
The electrons belong to the entire atom and are not constrained to any orbital. One uses orbitals to construct the wave function. One must be sure that the set of orbitals, i.e. the basis set, is sufficiently flexible to describe completely the molecular species. You are dealing with an atomic species so a polarization basis set is probably not needed.
 
 Wayne E. Steinmetz
 Carnegie Professor of Chemistry
 Woodbadge Course Director
 Chemistry Department
 Pomona College
 645 North College Avenue
 Claremont, California 91711-6338
 USA
 phone: 1-909-621-8447
 FAX: 1-909-707-7726
 Email: wsteinmetz:at:pomona.edu
 WWW: pages.pomona.edu/~wsteinmetz
 
 -----Original Message-----
 
*From:* Computational Chemistry List [mailto:chemistry-request:at:ccl.net] *On Behalf Of *Christopher Thompson
 *Sent:* Thursday, June 09, 2005 6:09 PM
 *To:* chemistry:at:ccl.net
 *Subject:* CCL:Defining orbitals
 
 Gday,
 
 I would like to do an MP2 calc on a Li- species in triplet state.
 
 With one electron in the s orbital and one in a p orbital,
 how can you constrain the electron to say the px orbital?
 
 Cheers,
 cdth:at:unimelb.edu.au
 
 Christopher Thompson
 Laser Spectroscopy Group
 School of Chemistry
 University of Melbourne
 
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