diff --git a/docs/advanced/input_files/input-main.md b/docs/advanced/input_files/input-main.md index 7c3628b9ff..b75eb7024b 100644 --- a/docs/advanced/input_files/input-main.md +++ b/docs/advanced/input_files/input-main.md @@ -3766,19 +3766,24 @@ These variables are used to control berry phase and wannier90 interface paramete - **Type**: Boolean - **Availability**: - - For PW and LCAO codes. if set to 1, occupations of bands will be setting of "ocp_set". - - For TDDFT in LCAO codes. if set to 1, occupations will be constrained since second ionic step. - - For OFDFT, this feature can't be used. + - For PW and LCAO codes: If set to 1, the band occupations will be determined by `ocp_set`. + - For RT-TDDFT in LCAO codes: If set to 1, same as above, but the occupations will be constrained starting from the second ionic step. + - For OFDFT: This feature is not available. - **Description**: -- True: fix the occupations of bands. -- False: do not fix the occupations of bands. +- True: Fixes the band occupations based on the values specified in `ocp_set`. +- False: Does not fix the band occupations. - **Default**: False ### ocp_set - **Type**: String -- **Description**: If ocp is True, the ocp_set is a string to set the number of occupancy, like '1 10 * 1 0 1' representing the 13 band occupancy, 12th band occupancy 0 and the rest 1, the code is parsing this string into an array through a regular expression. -- **Default**: none +- **Description**: + - If `ocp` is set to 1, `ocp_set` must be provided as a string specifying the occupation numbers for each band across all k-points. The format follows a space-separated pattern, where occupations are assigned sequentially to bands for each k-point. A shorthand notation `N*x` can be used to repeat a value `x` for `N` bands. + - Example: + - `1 10*1 0 1` represents occupations for 13 bands, where the 12th band is fully unoccupied (`0`), and all others are occupied (`1`). + - For a system with multiple k-points, the occupations must be specified for all k-points, following their order in the output file kpoints (may lead to fractional occupations). + - Incorrect specification of `ocp_set` could lead to inconsistencies in electron counting, causing the calculation to terminate with an error. +- **Default**: None [back to top](#full-list-of-input-keywords)