the newsletter of
collaborative computational project 1

Chemshell and QUASI

P. Sherwood
CCLRC Daresbury Laboratory, Daresbury, Warrington WA4 4AD
p.sherwood@dl.ac.uk

The ChemShell software for QM/MM Calculations

Work on the ChemShell QM/MM code [1] has continued in the framework of the QUASI project, (which finished in Q3 2001) [2]. Recent developments have included the following:

  • The development (within QUASI) of the HDLCOpt geometry optimiser for macromolecular systems [3]. This tool enables the popular delocalised internal coordinate approach to be used for macromolecules by subdividing the system into residues and defining the delocalised coordinates for each residue. Admixture of a contribution from the cartesian coordinates defines the relative position of the resiudes.
  • Support for a variety of new coupling models, including the Adjusted Connection Atom approach for semi-empirical calculations using the MNDO code [4]. A systematic analysis of the effect of choosing different QM/MM coupling approaches and QM regions sizes has been published by our collaborators in BASF and Muelheim [5].
  • Development of the interface to TURBOMOLE.
  • A solid-state embedding model for ionic materials, based on GULP and GAMESS-UK and incorporating mutual polarisation of the QM and MM regions [6]
  • The development of an open source GUI, using the tools developed in the CCP1 GUI project (see above). This will replace the existing Cerius-2 version.

In addition, the QUASI project has made extensive use of commodity cluster computing resources and the code has been ported to a number of parallel platforms. Porting to the HPCx national service are underway, and there is now a Windows PC version, built using the Cygwin environment.

A detailed description of the ChemShell QM/MM implementation and examples from the QUASI project covering industrial applications in the areas of metal oxide catalysis, enzyme modelling and catalysis by metal containing zeolites have now been submitted for publication [7].

Now that the QUASI project has finished it is planned to make the developments publically available and preparations for the next release, version 3.0, due in the Summer of 2003.

References and Links

[1] ChemShell Web page: www.cse.clrc.ac.uk/qcg/chemshell

[2] Project page: www.cse.clrc.ac.uk/qcg/quasi

[3] S.R. Billeter, A.J. Turner, W. Thiel, Phys. Chem. Chem. Phys. 2 (2000) 2177-86.

[4] I. Antes, W. Thiel, J. Phys. Chem. A 103 (1999) 9290-95.

[5] C. Lennartz, A. Schaefer, F. Terstegen, W. Thiel, J. Phys. Chem. B 106 (2002) 1758-67.

[6] Assignment of the Complex Vibrational Spectra of the Hydrogenated ZnO Polar Surfaces using QM/MM Embedding S.A. French, A.A. Sokol, S.T. Bromley, C.R.A. Catlow, S.C. Rogers and P. Sherwood, J. Chem. Phys, 118, (2003) 317-320. and references therein.

[7] Paul Sherwood, Alex H. de Vries, Martyn F. Guest, Georg Schreckenbach, C. Richard A. Catlow, Samuel A. French, Alexey A. Sokol, Stefan T. Bromley, Walter Thiel, Alex J. Turner, Salomon Billeter, Frank Terstegen, Stephan Thiel, John Kendrick, Stephen C. Rogers, John Casci, Mike Watson, Frank King, Elly Karlsen, Merethe Sjovoll, Adil Fahmi, Ansgar Schaefer and Christian Lennartz. Submitted to J. Mol. Struct (Theochem).

 

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