Thank you for your reply.

I tried again. If I delete all angles in data file, it well wrong that

angle coefficient are not set. How can I deal with angle_coeff command when

there is no angles in data file?

the number of angle_coeff parameters depends on the number of angle

*types*, but not the number of angles. you can have angle types defined but

not yet any angles.

By the way, what is the right way to deal with a diatomic molecule's

angles setting in data and in file?

i already told you, that his is utter nonsense. you cannot have an angle

in a diatomic.

axel