Here, we list a rough overview of recent changes in FHI-aims. A complete record is available directly through the FHI-aims GitLab. Every user is welcome and encouraged to gain access to the FHI-aims GitLab. The GitLab repository is also the location where bug fixes, improvements etc. will be made available.

A final general note: Please have a look at the growing Wiki in the FHI-aims GitLab. You’ll find helpful information about compiling and running FHI-aims: https://aims-git.rz-berlin.mpg.de/aims/FHIaims/-/wikis/home

- A “unified interface” for DFPT has been created, affecting
calculations employing the keywords:
`DFPT vibration`

,`DFPT vibration_reduce_memory`

,`DFPT phonon`

,`DFPT phonon_reduce_memory`

,`DFPT polarizability`

and`DFPT dielectric`

. - These calculations now are called using the keywords
`electric_field_response DFPT`

,`atomic_pert_response DFPT`

and`calculate_friction DFPT`

. - By default, these calculations now use a common DFPT module rather than separate implementations.
- There may be some performance changes. These changes should make the code more readable and future proof.
- The previous behaviour should be recoverable by employing
`dfpt_centralised .false.`

- Legacy capabilities provide warning messages to indicate that they will soon be retired, and are no longer supported.
- Some DFPT keywords have changed case to be more consistent, these
include:
`DFPT_sc_accuracy_dm`

–>`dfpt_sc_accuracy_dm`

,`DFPT_mixing`

—>`dfpt_mixing`

- The manual has been updated to reflect these changes. Please report any issues you come across.

- Implemented
`periodic_gw_self_energy_restart`

keyword to allow read/write correlation self-energy to redo analytic continuation and solving quasi-particle equation for periodic G0W0. Added relevant regression testcase`NaCl_G0W0_read_selfe`

. - Implemented
`periodic_gw_full_matrix`

keyword to switch on the calculation of full self-energy matrices for periodic G0W0 and`self_energy_matrix output`

keyword to export them in ELSI CSC format. Added relevant regression testcase`C_G0W0_full_sematrix`

. - Ensure that periodic GW calculation runs only when requested with
`band`

and/or`gw_regular_kgrid`

output keywords switched on. - Implemented spectral function calculation in periodic G0W0 based on diagonal approximation of self-energy matrix.

- Enable band structure calculations for hybrid functionals with small s.c.f. k-grids, down to Gamma point only.
- Implemented check for safe lower bounds of the s.c.f. k-grid in the hybrid band structure calculation.
- Bug fixes in the Fourier interpolation of Fock matrix elements.
`exx_band_structure_version 1`

is now the default for hybrid band structure calculations.

- Performance enhancements for RPA forces for solids (Muhammad Tahir).
`use_local_index`

is set to`.true.`

by default if a large-scale calculation is requested, with a large-scale calculation defined as one with 100 or more atoms (Konstantin Lion).- Added check and warning for charge integration error. Stop the code
if deviation to total charge exceeds 1E-5. Check can be disabled by
`setting override_error_charge_integration .true.`

in control file (Konstantin Lion). - Scalapack functionality has been added for the
`dos_kgrid_factors`

keyword. Existing code has been refactored to utilise many of the same routines as band structure calculations. Bug fix for hybrid functionals when combined with`symmetry_reduced_k_grid = .true.`

(James Green). - Restructuring of external libraries to all appear in the
`external_libraries`

folder (Sebastian Kokott). - Added periodic PBE0 test case
`MgO_pbe0`

(Sebastian Kokott). - Bug fixes for emptium 2020 species defaults (Sebastian Kokott).
- Bug fixes for
`load_balancing`

(Sebastian Kokott). - Bug fix for nonlocal core correction forces (Gabriel Bramley).
- Implemented
`hf_exchange_mat`

output keyword to export k-space EXX matrices in ELSI CSC format. Implemented ELSI CSC matrix comparison in testsuite backend (Minye Zhang). - Internal ELSI updated to commit 2d8fdec1.