A quick glance at the code seems to indicate that cell_dofree='ibrav+something' is implemented only for BFGS minimization, not for variable-cell molecular dynamics
Paolo On Mon, Mar 7, 2022 at 5:14 PM Tianhua Wang via users < [email protected]> wrote: > Dear Quantum ESPRESSO developers, > I am doing the cell optimization for cassiterite (SnO2) using the > variable cell shape molecular dynamics (i.e., *cell_dynamics='damp-w'*) > in QE 7.0. I had set *ibrav=6* for the crystal of cassiterite, and wanted > to constrain *cell_dofree='ibrav+shape'* during the optimization. > However, I found the none-zero values of v1_y&z, v2_x&z, v3_x&y in the > output file, e.g., > > *CELL_PARAMETERS (alat= 8.95238858)* > * 0.999715701 0.000000089 -0.000000001* > * 0.000000089 0.999715701 -0.000000001* > * -0.000000001 -0.000000001 0.672987836* > > which was not absolutely consistent with the initial ibrav choice (i.e., > *ibrav=6*). Then I tested the performance of *cell_dofree='ibrav'*, and > found the same phenomenon. It seems that the *cell_dofree* command does > not strictly constrain the initial ibrav choice. I also tested > *cell_dofree='xyz+shape'* although I had guessed that it did not work. > I am wondering if there is any way to strictly achieve > *cell_dofree='ibrav+shape'* (which is equal to *cell_dofree='xyz+shape'* > in this case) during the cell optimization. Perhaps another solution is to > fix the angles during the cell optimization, but how to achieve? My input > file is attached for reference. > Thank you for your time and I am looking forward to your reply. > Sincerely, > Tianhua Wang > > ------------------------------ > Tianhua Wang > State Key Laboratory for Mineral Deposits Research > School of Earth Sciences and Engineering > Nanjing University > 163 Xianlin Avenue, Nanjing > Jiangsu 210023, China > > > _______________________________________________ > The Quantum ESPRESSO community stands by the Ukrainian > people and expresses its concerns about the devastating > effects that the Russian military offensive has on their > country and on the free and peaceful scientific, cultural, > and economic cooperation amongst peoples > _______________________________________________ > Quantum ESPRESSO is supported by MaX (www.max-centre.eu) > users mailing list [email protected] > https://lists.quantum-espresso.org/mailman/listinfo/users -- Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche, Univ. Udine, via delle Scienze 206, 33100 Udine, Italy Phone +39-0432-558216, fax +39-0432-558222
_______________________________________________ The Quantum ESPRESSO community stands by the Ukrainian people and expresses its concerns about the devastating effects that the Russian military offensive has on their country and on the free and peaceful scientific, cultural, and economic cooperation amongst peoples _______________________________________________ Quantum ESPRESSO is supported by MaX (www.max-centre.eu) users mailing list [email protected] https://lists.quantum-espresso.org/mailman/listinfo/users
