THERMO_PW computes material properties. At low level, it calls QUANTUM ESPRESSO routines and, at high level, it has pre-processing tools to reduce the information provided by the user and post-processing tools that use the output of QUANTUM ESPRESSO to produce plots of material properties directly comparable with experiment.

THERMO_PW has the following directory structure, contained in a directory
`thermo_pw/` that should be put in the root directory of QUANTUM ESPRESSO:

Doc/ |
: contains this user's guide and other documentation |

examples/ |
: some examples |

examples_qe/ |
: QUANTUM ESPRESSO examples run using THERMO_PW |

inputs/ |
: a collection of useful inputs |

pseudo_test/ |
: a collection of inputs to test a pseudopotential library |

space_groups/ |
: a collection of structures for many space groups |

lib/ |
: source files for modules used by THERMO_PW |

qe/ |
: routines of QUANTUM ESPRESSO that require some |

change | |

src/ |
: source files for THERMO_PW |

tools/ |
: source files for auxiliary tools |

tools_input/ |
: examples of inputs for the auxiliary tools |

The THERMO_PW package can calculate the following quantities:

- Plot of the Brillouin zone (the structure can be seen by reading the
input of THERMO_PW by the
`XCrySDen`program). - Plot of the X-rays powder diffraction pattern of the input crystal.
- Total energy at fixed geometry.
- Total energy as a function of the kinetic energy cut-off.
- Total energy as a function of
**k**-points and smearing. - Electronic band structure at fixed geometry.
- Electronic density of states at fixed geometry. Electronic thermodynamic
properties: energy, free energy, entropy, and heat capacity.
- Electronic heat capacity as a function of temperature (for metals only).
- Complex dielectric constant as a function of the complex
frequency 1#1
at fixed geometry. Complex index of refraction for all systems except monoclinic and triclinic. Reflectivity at normal incidence and adsorption coefficient for cubic solids. - Inverse dielectric constant at a given wavevector
**q**as a function of the complex frequency 1#1at fixed geometry. - Phonon frequencies at fixed geometry.
- Phonon dispersions at fixed geometry and harmonic
thermodynamic properties: vibrational energy, vibrational free energy,
vibrational entropy, and constant volume heat capacity as a function of
temperature. Atomic Debye-Waller factors as a function of temperature.
- Frozen ions and relaxed ions elastic constants at fixed geometry.
- Relaxed ions temperature dependent elastic constants at fixed
unperturbed geometry.
- Fit of the total energy as a function of the lattice parameters with
a quadratic or quartic polynomial and determination of equilibrium lattice
parameters. Murnaghan or (third or fourth order) Birch-Murnaghan fit.
Enthalpy as a function of pressure. Crystal
parameters and volume as a function of pressure.
- Electronic band structure at the minimum of the total energy.
- Electronic density of states at the minimum of the total energy.
Electronic thermodynamic properties.
- Complex dielectric constant as a function of the complex
frequency 1#1
at the minimum of the total energy. Complex index of refraction for all systems except monoclinic and triclinic. Reflectivity at normal incidence and adsorption coefficient for cubic solids. - Inverse dielectric constant at a given wavevector
**q**as a function of the complex frequency 1#1at the minimum of the total energy. - Phonon frequencies at the minimum of the total energy.
- Phonon dispersions and harmonic thermodynamic quantities
at the minimum of the total energy.
- Frozen ions and relaxed ions elastic constants at the minimum of the total
energy.
- Anharmonic properties within the quasi-harmonic approximation:
lattice parameters, thermal expansion tensor, volume, volume thermal
expansion, and constant strain heat capacity as a function of temperature;
phonon frequencies and mode Grüneisen parameters interpolated at a given
geometry or at the equilibrium geometry at a given temperature
(limited to cubic, tetragonal, orthorhombic, and hexagonal systems).
Bulk modulus and pressure derivative of the bulk modulus, isobaric heat
capacity, isoentropic bulk modulus, and average Grüneisen parameter as
a function of temperature (limited to cubic systems).
Minimum Helmholtz (or Gibbs at finite pressures) free energy
as a function of temperature.
- Isothermal and isoentropic elastic constants and
elastic compliances as a function of temperature within the ``quasi-static''
approximation.
- Isothermal and isoentropic elastic constants and
elastic compliances as a function of temperature within the
``quasi-harmonic'' approximation.
- Surface band structure identification and plot of the projected bulk
band structure.

THERMO_PW can run on both serial and parallel machines using all
the parallellization options of QUANTUM ESPRESSO. Moreover, THERMO_PW can run using
several images.
When possible, the image parallelization is used in an asynchronous way.
One image takes the role of master and distributes the work
to all the images that carry it out independently. Presently
the total energies of several geometries for the determination of the
equilibrium geometry are calculated in parallel when
there are several images. Stresses or total energies at different strained
geometries needed for the calculation of the elastic constants are
calculated in parallel.
The phonon calculations are carried out in parallel, each image doing one
irreducible representation of one **q** point. For frequency dependent
calculation, each frequency, or group of frequencies, can be calculated
in parallel by different images.
The phonon dispersions of several geometries needed
for the quasi-harmonic calculation of the thermodynamic properties or
of the elastic constants can be calculated in parallel (one geometry at
a time or all geometries together).