Hi, does Q-Chem support (or plans to implement) Mixed-Reference Spin-Flip Time-Dependent Density Functional Theory (MRSF-TDDFT)? Here are some related links:
https://doi.org/10.1021/acs.jpclett.3c02296
GitHub - Open-Quantum-Platform/openqp: The main repository of Open Quantum Platform (OpenQP)
The feature is currently missing in Q-Chem. You can track the User Manual of future Q-Chem versions to know when it is available for deployment.
You can use spin-adapted spin-flip (SA-SF) TDDFT, which shares many of the same advantages, although there are no gradients for it in Q-Chem.
https://doi.org/10.1063/1.4937571