This is the data file associated with the publication "User-defined Electrostatic Potentials in DFT Supercell Calculations: Implementation and Application to Electrified Interfaces"
H_in_constant_field is the example of one H atom in a constant field (Figure 2b).
CCE is the Ne computational counter electrode (Figure 3a).
CDCE is the charge density counter electrode (Figure 3b).
At the beginning of each vasp_plugin.py file, there are calculation specific parameters that need to be adapted for each system. The units are eV for energy, eV/Å for force, Å for length,
Q_pos is the position of the counter electrode in Cartesian coordinate. In the examples, the conter electrode is a Gaussian wall which is constant in the x and y direction, so the x and y coordinates here do not change the setup.
Q0 is the charge of the counter electrode at step 0.
nelect_neutral is the total number of electrons in the system when the cell is charge-neutral. This number is used for checking the charge normalization.
grid_roll_frac is only used to compute the dipole correction in the python plugin. When integrating the charge density to get the dipole moment, the charge density is rolled in the z direction by grid_roll_frac (in fractional coordinate). This is to ensure that the electron charge density and the core charge density of an given atom stay in the same periodic image. In other words, after the rolling, the charge density at z = 0 should be 0.
grid_position_frac is the z position of the dipole correction (fractional coordinate).
width_wall is the width of the wall for confining water in CDCE.
pos_right_wall is the z position of the wall for confining water in CDCE (Cartesian coordinate).
i_Ne is the index of the Ne element following the order in POSCAR. The starting index is 0. (For example, if the element order in POSCAR is "Au Ne H O", i_Ne should be 1.)
n_elements is the total number of element. (If the element order in POSCAR is "Au Ne H O", n_elements should be 4.)
n_Ne is the total number of Ne atoms.
phi0 is the target electrode potential measured at the dipole correction (see the discussion of the thermopotentiostat in the paper)
tau and temperature determines the fluctuation and disspation of the thermopotentiostat. (See the discussions in paper, Eq. 6.)
C0 is the bare capacitance of the electrodes in vacuum, which is calculated by C0 = eps0*A/d_electrode. Here eps0 is the vacuum permitivity, A the surface area, and d_electrode the distance between the two electrode.