Dear Users,

I have optimized structures using RI-DFT (PBE0/def2-SVP/D3-BJ) while using COSMO. This means I have to calculate my frequencies numerically using `NumForce -central -ri`. Is it possible to recalculate these modes in the gas phase without reoptimizing my structure? I have tried the following:

1. Optimize in COSMO, then remove the COSMO information from the control file and run aoforce. aoforce failed with no error message, it got stuck (shown below) and increasing $maxcor did not help

` Nonorthonormal Krylov Space Iteration`

total number of roots to be determined: 216

maximum core memory set to 500 MB,

corresponding to 20 vectors in CAO basis

maximum number of simultaneously treated vectors (including degeneracy): 216

Recommendation for optimum performance: Increase the maximum amount of

allocatable core memory (e.g. $rpacor, $maxcor) to 5400 MB or to the

maximum amount of core memory available on your machine.

Iteration IRREP Converged Max. Euclidean

roots residual norm

2. The same as above but run `NumForce -central -ri`. In this case the calculation fails when checking the gradient norm

`CHECKING GRADIENT NORM`

gradient norm : 0.97432950E-01

No stationary point of energy, therefore no 2nd derivatives, dempsey!

3. I then tried the same but skipping the gradient check using `NumForce -central -ri -c`. This progresses the NumForce calculation but unsurprisingly I get imaginary modes. NumForce tried to warn me!

Is it possible to do what I am trying, or is it necessary to reoptimize in the gas phase? The reason I am trying this is because some of my thermodynamic data does not follow a trend we expected, and so I am thinking it could be that it could be and issue with COSMO frequencies and/or numerical error, hence me wanting to compare to gas phase analytical frequencies. Unfortunately, my structures do not optimize well in the gas phase.

Best,

Ryan