Knowledge Base

When I run an IRC calculation it defaults to Downhill mode and does not progress in both the forward and reverse directions. What can I do about it?

This can happen when the convergence criteria satisfied by the initial Jaguar transition state calculation isn't recognized as satisfying the convergence criteria for the IRC calculation because the TS calculation has ended on "flexible" grounds. The flexible criteria improve efficiency in general as a calculation can be very nearly converged on all criteria, or some components of the convergence criteria are highly converged.

You can make the convergence criteria of the TS optimization the same as those used by the IRC calculation by setting


in the gen section of the input file.

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