*From*: Igors Mihailovs <igors.mihailovs0]|[gmail.com>*Subject*: CCL: Spin contamination increased by annihilation of the first-order contaminant*Date*: Fri, 1 May 2015 18:00:58 +0300

Dear all,

I was quite surprised when,
during stability analysis of my wavefunction and subsequent reoptimization of it
in unrestricted space, the spin contamination was not descreased by removal of
the first-order contaminant:SCF Done: E(RHF) = -2277.17663511 A.U. after 1 cycles

NFock= 1 Conv=0.39D-08 -V/T= 2.0012

[..]

The wavefunction has an RHF -> UHF instability.

The two search directions are symmetric.

[..]

SCF Done: E(UHF) = -2277.19705082 a.u. after 42 cycles

Convg = 0.4967D-05 164 Fock formations.

S**2 = 2.1080 -V/T = 2.0009

<Sx>= 0.0000 <Sy>= 0.0000 <Sz>= 0.0000 <S**2>= 2.1080 S= 1.0356

<L.S>= 0.000000000000E+00

Annihilation of the first spin contaminant:

S**2 before annihilation 2.1080, after 8.9661

Looking
forward to Your help,

Igors Mihailovs (engineer)

Institute
of Solid State Physics

University of
Latvia