[Wien] CRITIC: a topological analysis program for WIEN2k

[Alberto Otero de la Roza]

Dear WIEN2k users,

 We have developed critic, a new code for the topological (QTAIM,
Bader) analysis of the electron density provided by WIEN. In this first
version, we have tried to provide the basic capabilities for a full
Atoms in Molecules study. A brief description of the features of
critic is:

* Fast and completely automatic localization of the critical points
  (CPs) in the unit cell. Using the symmetry information provided in
  the struct file, the irreducible wedge of the Wigner-Seitz cell is
  calculated, and used to place the seeds for a Newton-Raphson
  algorithm. The complete list of CPs is presented in the output,
  along with their properties (density, laplacian,...). The
  localization of all the CPs is usually completed within seconds to
  minutes.

* Atomic basin integration using a quadrature scheme plus a bisection
  strategy.

* Lots of ways of representing the density, laplacian and gradient
  vector field: 1d, 2d, 3d, contour plots, basin plots, 2d and 3d maps
  of flux lines,... These capabilities are enhanced by the use of
  external graphical programs, with which critic interfaces: gnuplot,
  geomview (http://www.geomview.org/), tessel
  (http://web.uniovi.es/qcg/tessel/tessel.html),...

* Additionally to WIEN2k, critic can read densities from other
  sources, applying common techniques to all of them.

* Critic is publicly available under the GPL licence. It has been
  published recently together with an article in Computer Physics
  Communications (1), and is downloadable from the CPC library or upon
  request to us.

(1) A. Otero-de-la-Roza, M.A. Blanco, A. Martín-Pendás and Víctor
Luaña, Critic: a new program for the topological analysis of
solid-state electron densities, Comput. Phys. Comm. 180 (2009)
157--166.

We are currently working in a new version of critic (critic2) where we
intend to implement lots of new features such as the use of different
scalar fields (laplacian, ELF, electrostatic potential, etc.), the
possibility of reading the electron density from a wider range of
sources,... This new code is not ready for public distribution. If you
are interested in the implementation of any particular feature, please
contact with us.

The development of this first version of critic is frozen,
limiting to bug fixes and small updates. However, we will gladly
provide the users of critic with technical support, and we would
appreciate very much any comment about the program.

Best wishes,

Alberto

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Alberto Otero de la Roza
PhD Student
Departamento de Química Física y Analítica.
Universidad de Oviedo, 33006 Oviedo, Spain.
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