delta_spin variable

NAME

  delta_spin -number of spin excitations

DESCRIPTION

The delta_spin variable determines the number of electrons promoted from down spin to up spin. The default value of delta_spin is 0. The total spin depends on the value of delta_spin and on the total number of electrons. The value of delta_spin is ignored if spin is OFF.

The following table summarizes the use of the delta_spin variable.
 

#electrons
delta_spin
total spin
even
0
0
odd
0
1/2
even
1
1
odd
1
3/2
even
2
2

EXAMPLE

The oxygen dimer's triplet ground state can be calculated using delta_spin=1.

DEFAULT VALUE

0

ALLOWED VALUES

non-negative integers

RELATED INFORMATION

spin


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