# CCL:G: (correction) Energy change upon swapping two orbitals in Gaussian
98

*From*: "Yutao Yue" <Yutao.Yue : gmail.com>
*Subject*: CCL:G: (correction) Energy change upon swapping two
orbitals in Gaussian 98
*Date*: Thu, 12 Mar 2009 10:54:53 -0400

Sent to CCL by: "Yutao Yue" [Yutao.Yue- -gmail.com]
(sorry the energy changes are 0.02 a.u., NOT 0.2 a.u.)
Dear All,
I have a successful G98 single point calculation (UBLYP/6-31G*) on a
metal-containing system of around 70 atoms. I use the result MOs as initial
guess, but swapped the two highest occupied beta orbitals (which are supposed to
be highly competing with each other) upon reading in the initial guess, to do
another G98 single point calculation on the same system. I then arrived at a
solution that, the frontier orbitals are almost identical to the original
solution including the ordering of the beta orbitals, while the single point
energy is 0.02 a.u. lower!
Similar calculations was done with UBPW91/6-31G*, and again the orbitals go back
to original ordering, but the single point energy is 0.02 a.u. higher now!
Anybody have any idea about those energy changes?
Thanks a lot and wish everybody a nice day!
-Yutao Yue