Help needed with SCF convergence
I am searching the energy surface of a triatomic molecule
(doublet) with ROHF method and got convergence problem whenever I try
to bend the molecule. The scf procedure goes okay until the total
energy difference between two consecutive iteration steps is at the
7th decimal place. Then the difference remains almost constant and
the iteration goes on forever.
I tried vshift option with g92 but it didn't work. G92 manual
says scf=qc does not apply to ROHF. The program I am using now is
meldf. With meldf, sometimes it works, sometimes it doesn't, even if
the guess is from a previous run with a smaller angle.
Can anyone give me advices? Thanks!