Water autoionization (2019) - CP2K RETIS (reconstructed TISMOL port)
===================================================================

Ab-initio (CP2K) RETIS study of the local initiation conditions for water
autoionization.

Paper:
  M. Moqadam, A. Lervik, E. Riccardi, V. Venkatraman, B. K. Alsberg and
  T. S. van Erp, "Local initiation conditions for water autoionization",
  Proc. Natl. Acad. Sci. U.S.A. 115, E4569-E4576 (2018).
  https://doi.org/10.1073/pnas.1714070115


IMPORTANT - this is a reconstruction
------------------------------------
The original study was run with TISMOL, the Fortran predecessor of PyRETIS,
which is no longer supported. The original TISMOL inputs are preserved under
tismol_original/ for reference. The PyRETIS version here was reconstructed
from them and has NOT been validated to reproduce the published numbers.

In particular, TISMOL's reaction coordinate ("H2OMAX DISTANCE") source code is
not part of these files, so the order parameter in orderp.py is a documented
*reconstruction*: the largest, over all hydrogens, of the distance from that
hydrogen to its nearest oxygen (the "most detached proton"). This is physically
consistent with autoionization and with the original interface set
(~1.07 to 10 Angstrom), but confirm it against the original definition before
using the results quantitatively.


Files
-----
  retis.rst          PyRETIS 3 input    (pyretisrun -i retis.rst)
  retis.toml         PyRETIS 4 input    (pyretisrun -i retis.toml)
  orderp.py          reconstructed order parameter (MaxDetachedProton)
  cp2k_input/        CP2K input (cp2k.inp assembled from the TISMOL CP2K
                     templates, initial.xyz = 32 waters, basis sets,
                     potentials)
  tismol_original/   the original TISMOL inputs (input.TISMOL, the CP2K
                     HEAD/TAIL fragments, geometries 000-020) - reference only


Requirements
------------
  * CP2K (BLYP/GTH; tested with cp2k.popt)


Status
------
The input parses, the reconstructed order parameter evaluates correctly on the
initial geometry, and CP2K launches and runs the DFT. This is a 96-atom
(32 water) BLYP system: a single DFT step is very expensive - use HPC for any
real run. Reduce "steps" for a quick functional check.


How to run
----------
  PyRETIS 3:   pyretisrun -i retis.rst
  PyRETIS 4:   pyretisrun -i retis.toml