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Input parameters in input.in

Input parameters that should be specified in input.in are listed below in the following format:

Keyword TYPE
Default value Available values
Detailed description

All inputs are case-sensitive. Keywords listed in the alphabetical order:

[Mandatory keywords] calc_method , calc_mode , pseudo_dir , qe_save_dir

[Optional keywords] A_dn_dn , A_up_dn , A_up_up , charge_tolerance , energy_tolerance , force_tolerance , includes_div_correction , is_heg , max_num_blocks_david , max_num_ionic_steps , max_num_iterations , mixes_density_matrix , mixing_beta , num_bands_tc , num_refresh_david , reads_crystal_structure , restarts , smearing_mode , smearing_width

Mandatory Keywords

calc_method STRING
Mandatory (no default value) FREE, HF, TC, BITC
Calculation method: free-electron mode (FREE), Hartree-Fock (HF), transcorrelated (TC),
bi-orthogonal transcorrelated (BITC) methods. No electron-electron interaction is
considered for FREE, i.e., the kinetic energy and pseudopotentials are only considered.
calc_mode STRING
Mandatory (no default value) SCF, BAND
Calculation mode. BAND calculation should be performed after SCF calculation.
pseudo_dir STRING
Mandatory (no default value) any
A directory where pseudopotential files are placed, e.g., /home/user/where_pseudopot_are_placed
qe_save_dir STRING
Mandatory (no default value) any
A save directory created by QE, e.g., /home/user/where_QEcalc_was_performed/prefix.save

Optional keywords

A_dn_dn REAL
Default: 1.0 any
A_{\downarrow,\downarrow} in the RPA-type Jastrow function, \frac{A_{\sigma, \sigma'}}{|{\bf r}-{\bf r'}|}(1-e^{-|{\bf r}-{\bf r'}|/C_{\sigma,\sigma'}}), normalized by A_0 = 1/\sqrt{4 \pi n},
the value for the homogeneous electron gas having the same electron density n of the system.
For example, A_dn_dn = 0.8 means A_{\downarrow,\downarrow}=0.8A_0.
C_{\downarrow,\downarrow} is determined so as to satisfy the cusp condition. Not used for calc_method = FREE or HF.
A_up_dn REAL
Default: 1.0 any
A_{\uparrow,\downarrow}, same as A_dn_dn. A_{\uparrow,\downarrow}=A_{\downarrow,\uparrow} is assumed.
A_up_up REAL
Default: 1.0 any
A_{\uparrow,\uparrow}, same as A_dn_dn. Users cannot specify different values for A_up_up and
A_dn_dn in non-spin-polarized calculation.
charge_tolerance REAL
Default: 1e-5 (1e-4 for ver.1.2 and before) \geq 0
In e^-. Convergence criteria for the charge density, used only for calc_mode = SCF.
energy_tolerance REAL
Default: 1e-6 (1e-5 for ver.1.2 and before) \geq 0
In Ht. Convergence criteria for the total energy (calc_mode = SCF) or a sum of eigenvalues (BAND).
force_tolerance (from ver.1.3) REAL
Default: 1e-2 \geq 0
In eV/ang. Convergence criteria for the force in structural optimization (see max_num_ionic_steps)
includes_div_correction BOOLEAN
Default: true true, false
Whether the divergence correction in the reciprocal space is included. See our paper:
is_heg BOOLEAN
Default: false true, false
Switches on the homogeneous-electron-gas mode where pseudopotentials and the Ewald energy
are ignored. (i.e., energy contribution from a lattice is ignored.)
max_num_blocks_david INTEGER
Default: 2 \geq 2
This keywords determines a size of subspace dimension for diagonalization.
subspace dimension = max_num_blocks_david \times num_bands_tc.
Increasing this value can improve convergence while computational time is proportional to it.
max_num_iterations INTEGER
Default: 30 for calc_mode = SCF, 15 for calc_mode = BAND \geq 0
Maximum number of iterations for the self-consistent-field loop (Also needed for calc_mode = BAND).
max_num_ionic_steps (from ver.1.3) INTEGER
Default: 0 \geq 0
Maximum number of structural-optimization steps. Structural optimization is switched on when
calc_mode = SCF and is_heg = false and max_num_ionic_steps > 0 and calc_method = HF or BITC.
mixes_density_matrix BOOLEAN
Default: false true, false
The density matrix (true) or the density (false) is used for mixing. The former with a small mixing_beta
can improve the convergence of calculation while computational time will be longer (by about a
factor of two). Used only for calc_mode = SCF. From ver.1.1.
mixing_beta REAL
Default: 0.7 > 0
Mixing ratio for linear mixing: new density (or density matrix) = mixing_beta \times new density +
(1- mixing_beta )\times old density. Used only for calc_mode = SCF.
num_bands_tc INTEGER
Default: nbnd in QE 1 \leq num_bands_tc \leq nbnd in QE
The number of bands for calculating eigenvalues. Also see max_num_blocks_david.
num_refresh_david INTEGER
Default: 1 \geq 1
Trial vectors are updated by num_refresh_david times for each update of the Fock operator.
reads_crystal_structure (from ver.1.3) BOOLEAN
Default: false true, false
When reads_crystal_structure = true, TC++ reads tc_crystal_structure.dat,
which is dumped in a previous structural-optimization run.
Note that this option is available only for the structural optimization (i.e. max_num_ionic_steps >0).
Please also see :doc:`how_to_use` describing tc_crystsal_structure.dat.
restarts BOOLEAN
Default: false true, false
When restarts = true, TC++ restarts calculation from a previous run.
smearing_mode STRING
Default: gaussian fixed, gaussian
fixed: fixed occupation for each k-point, gaussian: Gaussian smearing with smearing_width.
Recommended values are fixed for insulators and gaussian for metals.
smearing_width REAL
Default: 0.01 \geq 0 (A negative value will be ignored.)
In Ht. Not used for smearing_mode = fixed.

Examples of input.in

Example 1 (Minimum input.in for insulators)

calc_method    TC
calc_mode      SCF
pseudo_dir     /home/user/pseudopot
qe_save_dir    /home/user/QE/Si/prefix.save
smearing_mode  fixed

Example 2 (Minimum input.in for metals)

calc_method     TC
calc_mode       SCF
pseudo_dir      /home/user/pseudopot
qe_save_dir     /home/user/QE/Al/prefix.save
smearing_mode   gaussian
smearing_width  0.01

Example 3 (Restart calculation after Example 1)

calc_method     TC
calc_mode       SCF
pseudo_dir      /home/user/pseudopot
qe_save_dir     /home/user/QE/Si/prefix.save
smearing_mode   fixed
restarts        true

Example 4

calc_method     BITC
calc_mode       SCF
pseudo_dir      /home/user/pseudopot
qe_save_dir     /home/user/QE/something/prefix.save
smearing_mode   fixed
A_up_up         0.2
A_up_dn         0.2
A_dn_dn         0.2
max_num_iterations    15
max_num_blocks_david  5
mixes_density_matrix  true
mixing_beta     0.2

Example 5 (Structural optimization)

calc_method     BITC
calc_mode       SCF
pseudo_dir      /home/user/pseudopot
qe_save_dir     /home/user/QE/something/prefix.save
smearing_mode   fixed
max_num_iterations    20
max_num_ionic_steps   10

Example 6 (Restarted structural optimization reading tc_crystal_structure.dat)

calc_method     BITC
calc_mode       SCF
pseudo_dir      /home/user/pseudopot
qe_save_dir     /home/user/QE/something/prefix.save
smearing_mode   fixed
max_num_iterations       20
max_num_ionic_steps      10
reads_crystal_structure  true