### Optimization followed by vibrational analysis (numerical) with CCSD

Posted:

**18 Nov 2017, 06:56**Hello all,

I can easily run independent optimization and vibrational analysis (using numerical derivatives) using CCSD using two separate calculations.

However, I wonder if it is possible to combine these. Hence, first run optimization, and if the optimization succeeds then do vibrational analysis, (both under CCSD).

In my approach, I set tight optimization parameters and tight SCF convergence. Most of the times, optimization is successful. However, vibrational analysis does not proceed. I tried this with water and I get error about missing AOWOINT file, and I am unable to resolve this.

Could anyone drop a hint. Thank you.

I can easily run independent optimization and vibrational analysis (using numerical derivatives) using CCSD using two separate calculations.

However, I wonder if it is possible to combine these. Hence, first run optimization, and if the optimization succeeds then do vibrational analysis, (both under CCSD).

In my approach, I set tight optimization parameters and tight SCF convergence. Most of the times, optimization is successful. However, vibrational analysis does not proceed. I tried this with water and I get error about missing AOWOINT file, and I am unable to resolve this.

Could anyone drop a hint. Thank you.