First principles phonon calculations in materials science

A mixed-space approach to first-principles calculations of phonon frequencies for polar materials.

We propose a mixed-space approach using the accurate force constants calculated by the direct approach in real space and the dipole-dipole interactions calculated by linear response theory in reciprocal space, making the accurate prediction of phonon frequencies for polar materials possible using the direct approach as well as linear response theory. As examples, by using the present approach, ...

First-principles calculations of nonlinear optical susceptibility of inorganic materials

A method for calculations of the frequency-dependent nonlinear susceptibility of inorganic materials is implemented in the velocity gauge using a linear combination of atomic orbitals (LCAO) method within the framework of either the Hartree–Fock approximation or density functional theory. It is based on the standard time-dependent diagrammatic perturbation theory and has previously been applied...

Phonon anharmonicity of rutile SnO2 studied by Raman spectrometry and first principles calculations of the kinematics of phonon-phonon interactions

Raman spectra of rutile tin dioxide (SnO2) were measured at temperatures from 83 to 873 K. The pure anharmonicity from phonon-phonon interactions was found to be large and comparable to the quasiharmonicity. First-principles calculations of phonon dispersions were used to assess the kinematics of three-phonon and four-phonon processes. These kinematics were used to generate Raman peak widths an...

First Principles Calculations

Calculations of the linestrengths and transition frequencies of the forbidden pure rotational spectrum of Hz in the vibrationally excited v2 state are presented. These transitions occur in the far-infrared region, and their observation may be complicated by vi u2 difference transitions. Examples of these are also given. Forbidden rovibrational transition frequencies and linestrengths have also ...

Phonon conduction in PbSe, PbTe, and PbTe1xSex from first-principles calculations