Example:

CH$_2$ in the $^1$B$_2$ state from (3a$_1$)$^1$ (1b$_2$)$^1$, molecule in (x,z) plane.

$closed shells
  a1      1-2                                    ( 2 )
  b1      1                                      ( 2 )
$open shells type=1
  a1      3                                      ( 1 )
  b2      1                                      ( 1 )
$roothaan         1
$rohf
  3a1-3a1  a = 0      b = 0
  1b2-1b2  a = 0      b = 0
  3a1-1b2  a = 1      b = -2