The ZPL energy of internal optical transition in defect is estimated to be the difference between the excited state (calculated by constraining the excited state electronic configuration during relaxation) total energy and the ground state total energy. However, the constrain at the excited state can be done with LDIAG=.FALSE. or without it. LDIAG=.FALSE. do not allow rotation of orbitals during electronic optimization process and vice versa. Which is more accurate for calculating ZPL?
Hello, in constrained DFT calculations for ZPL (zero-phonon line) energy of defect-related internal optical transitions, the choice of whether or not to use LDIAG=.FALSE. depends on the specifics of your system and the accuracy you desire. Both approaches have their advantages and drawbacks.
Using LDIAG=.FALSE. ensures that the orbitals do not rotate during the electronic optimization process. This can be useful when you need to enforce a specific electronic configuration, such as in the case of an excited state. By not allowing the orbitals to rotate, you may obtain a more stable and well-defined excited state.
However, this constraint may also limit the convergence and accuracy of the calculation. By not allowing the orbitals to rotate, the system may not be able to find the true minimum energy configuration for the excited state. In some cases, this might lead to an overestimation or underestimation of the ZPL energy. On the other hand, if you allow for orbital rotations (LDIAG=.TRUE.), the system can explore a wider range of configurations, potentially leading to a more accurate ZPL energy calculation. However, this also increases the risk of inadvertently converging to a different electronic state than the one you're interested in, as the constraint may not be as strictly enforced. To determine which approach is more accurate for your specific system, you could perform a series of test calculations with both LDIAG=.FALSE. and LDIAG=.TRUE. By comparing the resulting ZPL energies and convergence behavior, you can make an informed decision on which approach is more suitable for your system. So the choice of whether or not to use LDIAG in constrained DFT calculations for ZPL energy depends on the balance between the desired accuracy and the need for enforcing a specific electronic configuration. It is recommended to perform test calculations using both approaches to determine the most suitable method for your specific system.
ORCA files I draw How to calculate the Files . I new one ORCA
- Badges
- Science topic
- Similar topics
- Social Science