You must preserve the proportion --and, if the displacements are complex, the phase differences- among the mode components.
Your procedure doesn't do that unless you write the displaced geometry in fractional coordinates and your system is orthorhombic. It's much simpler to use alat coordinates so that you can add the scaled displacement as it is. Pietro ________________________________ Da: users <[email protected]> per conto di Piotr Szkudlarek <[email protected]> Inviato: mercoledì 25 gennaio 2023 14:54 A: Quantum ESPRESSO users Forum <[email protected]> Oggetto: Re: [QE-users] R: R: Reading displacements from the matdyn.modes file Dear Pietro, to create the displaced geometries, I added the 1st, 3rd and 5th number in the matrix divided by x, y and z cell sizes and then multiplied by an arbitral scaling factor (in my case - 0.1)). Is that a proper way to create the displaced geometry? Yours sincerely., Piotr Szkudlarek śr., 25 sty 2023 o 14:48 Pietro Davide Delugas <[email protected]<mailto:[email protected]>> napisał(a): Dear Piotr It is just a normalized 3Xnat vector --normalized such that the sum of the squared moduli of all displacements yields one. They give you the relative amplitudes and phases of the atomic displacements in that mode. The net amplitude would depend on the energy stored in that mode and its reduced mass. Hope it helps Pietro ________________________________ Da: users <[email protected]<mailto:[email protected]>> per conto di Piotr Szkudlarek <[email protected]<mailto:[email protected]>> Inviato: mercoledì 25 gennaio 2023 13:22 A: Quantum ESPRESSO users Forum <[email protected]<mailto:[email protected]>> Oggetto: Re: [QE-users] R: Reading displacements from the matdyn.modes file Dear Pietro, Thank you very much for your answer. I have another question: are those numbers in Angstrom or what units? Regards, Piotr Szkudlarek pon., 23 sty 2023 o 11:28 Pietro Davide Delugas <[email protected]<mailto:[email protected]>> napisał(a): Hello Piotr The displacements' components are complex numbers; thus, six floats. Pietro ________________________________ Da: users <[email protected]<mailto:[email protected]>> per conto di Piotr Szkudlarek <[email protected]<mailto:[email protected]>> Inviato: lunedì 23 gennaio 2023 10:55 A: Quantum ESPRESSO users Forum <[email protected]<mailto:[email protected]>> Oggetto: [QE-users] Reading displacements from the matdyn.modes file Dear QE community, I would like to ask what is the meaning of 6 floats in matdyn.modes file. I can imagine that 3 of them show the coordinates of the displacements, but what are the other three? Also, which of them are the ones telling about the coordinates of the displacement? Best, Piotr Szkudlarek, University of Warsaw _______________________________________________ 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<http://www.max-centre.eu>) users mailing list [email protected]<mailto:[email protected]> https://lists.quantum-espresso.org/mailman/listinfo/users _______________________________________________ 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<http://www.max-centre.eu>) users mailing list [email protected]<mailto:[email protected]> https://lists.quantum-espresso.org/mailman/listinfo/users
_______________________________________________ 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
