Outputting Dipole Moment

Outputting Dipole Moment#

ABACUS can output the dipole moment by adding the keyword out_dipole in the INPUT file:

out_dipole             1

Supported Calculations#

This feature is available for all types of DFT calculations that use charge density:

  • KSDFT (Kohn-Sham DFT)

    • Plane wave (PW) basis

    • Linear combination of atomic orbitals (LCAO) basis

  • SDFT (Stochastic DFT)

  • OFDFT (Orbital-Free DFT)

  • TDDFT (Time-Dependent DFT)

Input Parameters#

Parameter

Type

Description

Default

out_dipole

Integer

Whether to output dipole moment

0

  • out_dipole = 0: Disable dipole output

  • out_dipole = 1: Enable dipole output

Output Files#

When out_dipole is set to 1, ABACUS will generate files named dipole_s${spin}.txt for each spin channel in the output directory.

For spin-polarized calculation (nspin=2):

  • dipole_s1.txt

  • dipole_s2.txt

For non-spin-polarized calculation (nspin=1):

  • dipole_s1.txt

Output Format#

The dipole output file contains one line for each ionic/electronic step:

step_index dipole_x dipole_y dipole_z

  • step_index: The current step number (starts from 1)

  • dipole_x, dipole_y, dipole_z: The Cartesian x, y, z components of the electronic dipole moment for the corresponding spin channel, in units of elementary charge times Bohr (\(e a_0\)).

These components refer to the Cartesian axes, including for nonorthogonal or rotated cells; they are not components along the lattice vectors. The electronic dipole includes the negative sign of the electron charge.

Example output:

1 -0.00123456 0.00234567 -0.00345678
2 -0.00123457 0.00234568 -0.00345679
...

Additional Information#

During the calculation, the dipole moment is also printed in the running_*.log file, including:

  • Electronic dipole moment

  • Ionic dipole moment

  • Total dipole moment

  • Total dipole moment norm

The log reports Cartesian components in the same units. The total dipole moment is the sum of the electronic and ionic dipoles, and its norm is calculated from these Cartesian components. The dipole_s${spin}.txt files contain only the electronic contribution.