Author Topic: many problems encoutered while I used TDDFT EGRAD for optimization...  (Read 3989 times)

Lohengrin

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dear all,
i often meet two sorts of troubles, especially in triplet pi-pi* excited state geometry optimizations:

1. the optimization died without any message error. it usually stopped after several cycles at an unconverged gradient -- around 0.1~0.3. and it would always stop at the same position if i redid it from a different initial geometry. eg. the first triplet pi-pi* state of acetaldehyde (C1), formaldehyde (Cs), and acetone (Cs).

2. usually occurs in triplet states as well with the following message:
MODTRACE: no modules on stack
Reference state is non-real unstable
egrad ended abnormally
error in gradient step (1)

i've heard that increasing the number of roots calculated and config of FERMI etc might help. but these didn't work at all!
anyone knows the recipe? Many Many Thanks!!