Qcserenity

[GitHub]: https://github.com/dftlibs/xcfun
[pybind11]: https://pybind11.readthedocs.io
[Doxygen]: http://doxygen.nl/
[breathe]: https://breathe.readthedocs.io/en/latest/
[Sphinx]: https://www.sphinx-doc.org/en/master/


Changelog
=========

--------------------------

Functionalities

- Designable density functionals in the input by mixing basic functionals (Anton Rikus)
- Stabilized Quasi-Newton Method (SQNM) optimizer for minima (Thorben Wiegmann)
- Added WF in DFT geometry optimizations for HF (Thorben Wiegmann)
- CHELPG and CM5 partial charges (Thorben Wiegmann)
- Approximate embedding electrostatics via partial charges (Lars Hellmann)
- Approximate embedding via the Loewdin expansion of kinetic energy expectation values
computed from non-orthogonal Slater determinants (Denis G. Artiukhin)
- TDDFT Gradients: restricted/unrestricted, LDA/GGA/hybrid and range-separated functionals, CIS/TDA/TDHF as well,
RI-J possible, but so far only for an isolated system (Anton Rikus)
- Added tasks for exporting and importing solvation models with corresponding solvent cavities and charges
to/from files that can be used by Serenity (Lukas Paetow)
- Transition, particle and hole densities can also be plotted for subsystem TDDFT (Anton Rikus)
- Transition and excited state densities from CC2/ADC(2) can be plotted (Anton Rikus)
- Read in external grid potential (Leon Fischer)
- Added a task that writes FCI dump files (Moritz Bensberg).
- Added a task that runs top-down embedding calculations without SCF-based orbital relaxation after subsystem
partitioning (Moritz Bensberg).
- Added a new embedding flavor, ALMO-MSDFT (Lukas Lampe).

Technical Features
- Added classes for easier calculation of gradient contributions from two-electron
integrals using the RI approximation and from one-electron integrals (Anton Rikus)
- Basis files can be directly read in Turbomole format (Anton Rikus)
- LRSCFTaskSettings are written on disk (Anton Rikus)
- Added test systems with converged LRSCF excitation vectors (Anton Rikus)
- Python wrapper published on PyPI, allowing `pip install qcserenity` (Anton Rikus)

--------------------------

Functionalities

- Added a task that provides direct access to integral files such as the core Hamiltonian (Moritz Bensberg)
- External charges may now be used as an additional potential and read from file (Moritz Bensberg)

Technical Features

- Negative numbers as input for unsigned variables are now taken as their absolute value and a warning is issued (Niklas Göllmann)
- SCF-Damping reworked internally (Lukas Paetow)

--------------------------

Functionalities

Technical Features

- Updated ATOM_SCF initial guess atom densities, now BHLYP in a MINAO basis (Nadim Ramez)
- Removed deprecated ATOM_DENS initial guess (Niklas Niemeyer)
- Moved fractional occupancy keyword to the system block (Niklas Niemeyer)

Linear-Response Framework

- CC2/ADC(2) ground- and excited-state densities and dipole moments (Niklas Niemeyer)
- CC2 dynamic polarizabilities and optical rotation (Niklas Niemeyer)
- Triplet excitation energies for CC2/ADC(2) (Niklas Niemeyer)
- Rework Kernel sigmavector (Niklas Niemeyer)
- "Monomer-RI" Coulomb interaction subsystem TDDFT (Niklas Niemeyer)
- TDDFT-ris (one aux. basis function per atom for TDDFT, Niklas Niemeyer)
- Experimental:
* Coupled CC2/ADC(2) excitation energies, transition moments, excited-state densities and response properties (Niklas Niemeyer)

-------------------------------

Functionalities

- Added two flavors of restricted open-shell HF and KS for the ground-state (Niklas Niemeyer)
- Fermi-shifted Huzinaga EO Kernel for subsystem TDDFT (Niklas Niemeyer)
- Laplace-Transform GW (Johannes Tölle, Niklas Niemeyer)
- Renamed ReadOrbitalsTask to OrbitalsIOTask (Niklas Göllmann)
- Added the functionality to write Turbomole files (Niklas Göllmann)
- Added the functionality to write Molden files for both spherical and cartesian harmonics (Niklas Göllmann)
- Added three schemes to generate complete basis function products for the Cholesky
decomposition framework: Simple, First, Complete (Lars Hellmann)
- Added the functionality to control density fitting for individual
contributions (Coulomb, exchange, long-range exchange, correlation)

-------------------------------

Functionalities

- Added MOM and IMOM DeltaScf methods (Niklas Niemeyer, Niklas Göllmann)

Linear-Response Framework

- Added triplet exctations for TDHF/TDDFT (Niklas Niemeyer)
- Added the following stability analyses for SCF wavefunctions and instability root following (Niklas Niemeyer)
- Real RHF -> Real RHF
- Real RHF -> Real UHF
- Real RHF -> Complex RHF
- Real UHF -> Real UHF
- Real UHF -> Complex UHF
- Added spin-flip TDHF/TDDFT (Niklas Niemeyer)

Bug Fixes

- Fixed a bug where the T0-correction failed for only 2 electrons.
- Fixed various incorrect settings files in the test resources.
- Fixed an error in FXDTask.cpp.
- Added a factor of one half for the restricted Levelshift potential to be consistent with the other EO potentials
- Serenity is now compilable on macOS, functioning memory management (Apple M1 Pro)