QM call was not successful,

[vrocha98]

Hello Sebastian!

I am using SHARC with the LVC approximation to run nonadiabatic excited-state dynamics for some organic molecules. Everything has been working perfectly.

In order to validate the LVC method for parametrizing excited states, I am running a single trajectory using SHARC/TDDFT. However, I encountered some errors that I don't know how to solve.

At a certain point during the dynamics, the following error occurs:

=============================================================
QM call was not successful, aborting the run.
Error code: 256

And in the ORCA.log file, there is an error that, as far as I understand, suggests that the T1 state becomes lower in energy than the S0 state. However, when I run data_extractor to monitor the energies in the energy.out file, this does not seem to happen. But T1 does get very close in energy to S0, and shortly after that, the calculation crashes with an error.

Have you ever encountered this kind of issue and might have some insight on how to fix it? I'm attaching the results. Thanks in advance!

TRAJ_00006.zip

[maisebastian]

Dear vrocha98,
indeed it seems that ORCA fails in the triplet TDDFT calculation. This can indeed happen when the ground state and the S1 becomes very small (DFT is a single-determinant/single-reference method that has problems with such things). However, in your case, the S0-S1 gap is more than 3eV, so it is unlikely that it is really a problem with a geometry where the S0 touches the higher states. Instead, you might have encountered a "triplet instability" problem. See, e.g., https://pubs.acs.org/doi/abs/10.1021/ct200651r. You can try to activate the Tamm-Dancoff approximation. This might help with your triplet state energies, and additionally is cheaper. Moreover, I would not recommend parametrizing LVC models with TDDFT without TDA, because the wave function overlaps computed during parametrization must be very precise, and without TDA, it is difficult to control the truncation of the excitation vectors. See https://pubs.acs.org/doi/full/10.1021/acs.jpca.4c07472.

Best,
Sebastian