This page gives hints on how to set parameters related to the phonon wavevectors (q-points) in DFPT calculations with the ABINIT package.
Like the electronic wavefunctions, the collective atomic displacements that are eigenmodes of the corresponding periodic Hamiltonian can be characterized by a wavevector, denoted q-point.
In ABINIT, DFPT calculations for one dataset are done for one specific q-point, that must be specified. In the simplest case, the user gives the corresponding q-point for each dataset, setting nqpt=1 and specifying the corresponding single qpt. However, very often, it is needed to run calculations for dozens or hundreds of q-points. Hence, the following mechanism has been set: the use can specify a set of q points, using input variables similar to the k-points, and then, for each dataset, the number of the q-point in the set is indicated thanks to iqpt. This applies to the generation of q-point grids as well as to q-point paths to produce phonon band structures.
Related Input Variables¶
- iqpt Index for QPoinT generation
- ngqpt Number of Grid points for Q PoinTs generation
- nqpt Number of Q - POINTs
- qptopt QPoinTs OPTion
- nshiftq Number of SHIFTs for Q point grids
- ph_intmeth PHonons: INTegration METHod
- ph_ndivsm PHonons: Number of DIVisions for sampling the SMallest segment
- ph_ngqpt PHonons: Number of Grid points for Q-PoinT mesh.
- ph_nqpath PHonons: Number of Q-points defining the PATH
- ph_nqshift PHonons: Number of Q-SHIFTs
- ph_qpath Phonons: Q-PATH
- ph_qshift PHonons: Q-SHIFTs for mesh.
- ph_smear PHonons: SMEARing factor
- ph_wstep PHonons: frequency(W) STEP.
- qpt Q PoinT
- qptnrm Q PoinTs NoRMalization
- qptrlatt Q - PoinTs grid: Real space LATTice
- shiftq SHIFT for Q points
- wtq WeighTs for the current Q-points
Selected Input Files¶
No input file associated to this topic.