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7 Phonon calculations

Phonon calculation is presently a two-step process. First, you have to find the ground-state atomic and electronic configuration; Second, you can calculate phonons using Density-Functional Perturbation Theory. Further processing to calculate Interatomic Force Constants, to add macroscopic electric field and impose Acoustic Sum Rules at q=0 may be needed. In the following, we will indicate by q the phonon wavevectors, while k will indicate Bloch vectors used for summing over the Brillouin Zone.

Since version 4.0 it is possible to safely stop execution of ph.x code using the same mechanism of the pw.x code, i.e. by creating a file prefix.EXIT in the working directory. Execution can be resumed by setting recover=.true. in the subsequent input data.



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Paolo Giannozzi 2011-07-17