A. Prior to version 6.6, once restart_mode=‘restart’ is stated, then Quantum Espresso would use previously calculated output files to obtain the necessary information for performing calculations, such as atomic coordinates and cell sizes.
However, If you perform a calculation in Quantum ESPRESSO version 6.6 or later using the vc-relax method, and then try to restart the calculation using the restart_mode you may encounter an error message such as “starting and expected charges different” or you may find that the calculation converges to the wrong energy.
Materials Square has updated its “Quantum Espresso” module to prevent it from being connected to calculations that used the vc-relax method to avoid the error described above.
To ensure accurate results when performing subsequent calculations after using the vc-relax method, the recommended workflow is as follows:
- Create a structural model using the “Structure Builder” module.
- Add the “Quantum Espresso” module and connect it to the Structure Builder in step 1 to perform the ‘vc-relax’ calculation.
- In the “Structure Builder” module, use the “Module” menu to import the final structure from the vc-relax calculation completed in step 2.
- Perform scf calculation by connecting the new “Quantum Espresso” module to the final structure. Add a new “Quantum Espresso” module and connect it to the final structure from step 3. Use this module to perform an SCF calculation
- Add a new “Quantum Espresso” module and connect it to the SCF calculation performed in step 4. Use this module to perform restart post-processing calculations, such as a nscf calculation.