Keywords: user_guide

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## 3.1 Compilation

Typing `make ph` from the root QUANTUM ESPRESSO directory, or `make` from the `PHonon` directory, produces the following codes:

- `PH/ph.x`: Calculates phonon frequencies and displacement patterns, dielectric tensors, effective charges (uses data produced by `pw.x`).
- `PH/dynmat.x`: applies various kinds of Acoustic Sum Rule (ASR), calculates LO-TO splitting at = 0 in insulators, IR and Raman cross sections (if the coefficients have been properly calculated), from the dynamical matrix produced by `ph.x`
- `PH/q2r.x`: calculates Interatomic Force Constants (IFC) in real space from dynamical matrices produced by `ph.x` on a regular q-grid
- `PH/matdyn.x`: produces phonon frequencies at a generic wave vector using the IFC file calculated by `q2r.x`; may also calculate phonon DOS, the electron-phonon coefficient λ, the function α2F(ω)
- `PH/lambda.x`: also calculates λ and α2F(ω), plus Tc for superconductivity using the McMillan formula
- `PH/alpha2f.x`: also calculates λ and α2F(ω). It is used together with the optimized tetrahedron method (`occupations="tetrahedra_opt"` in `pw.x`) and shifted q-grid (`lshiftq=.true.` in `ph.x`).
- `PH/fqha.x`: a simple code to calculate vibrational entropy with the quasi-harmonic approximation
- `PH/dvscf_q2r.x`: performs inverse Fourier transformation of phonon potential from a regular q grid to real space.
- `Gamma/phcg.x`: a version of `ph.x` that calculates phonons at = 0 using conjugate-gradient minimization of the density functional expanded to second-order. Only the Γ ( = 0) point is used for Brillouin zone integration. It is faster and takes less memory than `ph.x`, but does not support spin polarization, USPP and PAW.

Links to the main QUANTUM ESPRESSO `bin/` directory are automatically generated.

Next: 4 Using PHonon Up: 3 Installation Previous: 3 Installation Contents