[QE-users] Reduced mass?

[Pietro Davide Delugas]

Hello
Generally, the reduced mass of the phonon modes is not very useful because it is implicitly included in the normalization of their displacements, and introducing it explicitly would only complicate things.
However, one definition of the reduced mass could be:

[cid:adf309ce-e8ba-4316-be5b-240a7f203c74]
Where k is the index running on all atoms, m_k is the mass, and u_k are the displacements of the mode.


Here are some notes https://hackmd.io/@pietrodelugas/r1SykO511l
Pietro
________________________________
From: users <users-bounces at lists.quantum-espresso.org> on behalf of Andrii Shyichuk via users <users at lists.quantum-espresso.org>
Sent: Saturday, October 12, 2024 01:21
To: users at lists.quantum-espresso.org <users at lists.quantum-espresso.org>
Subject: [QE-users] Reduced mass?

Dear Users,

How do I get the reduced mass of a vibrational (phonon) mode from (I
guess) PH.X?

I assume it must be calculated somewhere, but it is not printed. It is
not mentioned in the PH manual (searched for "mass") and it looks like
nobody asked it here (searched for "reduced mass").

Thank you.

Best regards.

dr Andrii Shyichuk, Faculty of Chemistry, University of Wrocław



dr Andrii Shyichuk
ADIUNKT
Zakład Chemii Nieorganicznej, Wydział Chemii

Uniwersytet Wrocławski
ul. F. Joliot-Curie 14
50-383 Wrocław
tel. +48 71 375 72 65

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