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Program description   

deMon (density of Montréal) is a software package for density functional theory (DFT) [1-3] calculations. It uses the linear combination of Gaussian-type orbital (LCGTO) approach for the self-consistent solution of the Kohn-Sham (KS) DFT equations. The calculation of the four-center electron repulsion integrals is avoided by introducing an auxiliary function basis for the variational fitting of the Coulomb potential [4-6]. The main features of the deMon package are:

For further details concerning theory, implementation and program features see the deMon user's guide.

deMon2k citations

Version 3.x:

A.M. Koster, G. Geudtner, P. Calaminici, M.E. Casida, V.D. Dominguez, R. Flores-Moreno, G.U. Gamboa, A. Goursot, T. Heine, A. Ipatov, F. Janetzko, J.M. del Campo, J. U. Reveles, A. Vela, B. Zuniga-Gutierrez and D.R. Salahub, deMon2k, Version 3, The deMon developers, Cinvestav, Mexico City (2011).

Version 2.x:

A.M. Koster, P. Calaminici, M.E. Casida, V.D. Dominguez, Flores-Moreno, G. Geudtner, A. Goursot, T. Heine, A. Ipatov, F. Janetzko, J.M. del Campo, J.U. Reveles, A. Vela, B. Zuniga and D.R. Salahub, deMon2k, Version 2, The deMon developers, Cinvestav, Mexico City (2006).

Program branches and related programs   

The deMon2k program is developed by scientific groups all over the world. The current master version of deMon2k is described and can be downloaded from this web site. However, there exist several deMon2k branches and programs related to deMon2k, which have a different or extended functionality and might be based on an older master version. Please, see the following links for details and more information about functionality and reference to a deMon2k version number:

Program branches

Related programs


The game of the name

The first widely available version of deMon [7] appeared in 1992. deMon stands for densité de Montréal. The unusual capitalization emphasizes the roots of the code at the Université de Montréal (UdM) simultaneously by its implicit separation into two words [de-Mon(réal)] and by its resemblance to the main edifice of UdM with its tall central tower.

Program history

deMon2k history

One way to understand deMon is to look at it in its historical context [8]. During the 1970's Slater's Xalpha method had been tried and abandoned by quantum chemists. Part of the difficulty was in the scattered wave, muffin-tin implementation of the time. Major numerical improvements came about through the introduction of Gaussian-type orbitals (GTO) and the use of auxiliary fitting functions in the LCAO-Xalpha program [9,10]. This allowed GTO technology to be borrowed from existant ab initio codes. Other major advances were Axel Becke's introduction of efficient, accurate, atom-centered numerical integration, Vosko, Wilk and Nusair's parameterization of the local density approximation [11] based upon Ceperly and Alder's accurate quantum Monte Carlo calculations of the correlation energy of the homogeneous electron gas, as well as the emergence of good quality generalized gradient approximations such as those of Becke [12] and Perdew [13]. By the 1980's, it had become clear that it was time to update the old LCAO-Xalpha strategy and write a modern DFT program with analytic derivatives capable of automatic geometry optimizations. This goal was realized simultaneously in deMon and in another program (namely DGauss developed at Cray for use on their computers).

Shortly after its appearance the original deMon code was substantially modified for commercialization by BIOSYM Technologies. The beta-release of this version appeared in 1993. It was the basis of the deMon-KS1 [14] series of programs developed in Montreal until 1997. Meanwhile the original deMon version was further developed in Montpellier and Stockholm. These developments were initially independent from each other. In 1997 they merged to become the deMon-KS3 [15] series of programs.

Over the years, many important method developments in DFT can be attributed to work originating with deMon and related programs. This includes, but is not limited to, NMR chemical shifts [16] and time-dependent density functional theory [17]. Several different versions of deMon developed.

The AllChem [18] project started in Hannover in 1995 independently of the deMon project. The aim of this project was to write a well structured DFT code from scratch. The first AllChem version appeared in 1997. The structured programming of AllChem proved very useful for the development and testing of new DFT approaches and algorithms.

The deMon and AllChem developers agreed at the first deMon Developers meeting in Ottawa to merge their codes in order to keep a Tower of Babel from arising. As a result the new code couples the deMon functionality with the stable and efficient integral part from AllChem, including for example f, g and higher angular momentum type hermite Gaussian auxiliary functions. The merged code was presented for the first time at the third deMon Developers meeting in Geneva. The present version of the code is now known as deMon2k [19] to distinguish it from the earlier (premerge) codes.


[1] P. Hohenberg, W. Kohn, Phys. Rev. 136, B864 (1964).
[2] W. Kohn, L. J. Sham, Phys. Rev. 140, A1133 (1965).
[3] R. M. Dreizler, E.K.U. Gross, Density Functional Theory (Springer-Verlag, Berlin, 1990).
[4] B. I. Dunlap, J. W. D. Connolly, J. R. Sabin, J. Chem. Phys. 71, 4993 (1979).
[5] J. W. Mintmire, B. I. Dunlap, Phys. Rev. A 25, 88 (1982).
[6] J. W. Mintmire, J. R. Sabin, S. B. Trickey, Phys. Rev. B 26, 1743 (1982).
[7] Alain St-Amant, Ph.D. Thesis, Université de Montréal, 1992.
[8] D. R. Salahub, A. Goursot, J. Weber, A. M. Köster, and A. Vela, in Theory and Applications of Computational Chemistry: The First 40 Years. A Volume of Technical and Historical Perspectives, edited by C. E. Dykstra, G. Frenking, K.S. Kim, and G. E. Scuseria (Elsevier: 2005). “Applied Density Functional Theory and the deMon Codes: 1964-2004”
[9] H. Sambe and R. H. Felton, J. Chem. Phys. 62, 1122 (1975).
[10] B. I. Dunlap, J. W. D. Connolly, J. R. Sabin, J. Chem. Phys. 71, 3396 (1979).
[11] S. H. Vosko, L. Wilk, and M. Nusair, Can. J. Phys. 58, 1200 (1980).
[12] A. D. Becke, Phys. Rev. A 38, 3098 (1988).
[13] J. P. Perdew, Phys. Rev. B 33, 8822 (1986).
[14] M. E. Casida, C. Daul, A. Goursot, A. M. Köster, L. G. M. Pettersson, E. Proynov, A. St-Amant, D. R. Salahub, H. Duarte, N. Godbout, J. Guan, C. Jamorski, M. Leboeuf, V. Malkin, O. Malkina, F. Sim, A. Vela, deMon-KS Version 3.5, deMon Software, Montréal, 1996.
[15] M. E. Casida, C. Daul, A. Goursot, A. M. Köster, L. G. M. Pettersson, E. Proynov, A. St-Amant, D. R. Salahub, H. Duarte, N. Godbout, J. Guan, K. Hermann, C. Jamorski, M. Leboeuf, V. Malkin, O. Malkina, M. Nyberg, L. Pedocchi, F. Sim, L. Triguero, A. Vela, deMon Software, Montréal, 2001.
[16] V. G. Malkin, O. L. Malkina, M. E. Casida, and D. R. Salahub, J. Am. Chem. Soc. 116, 5898 (1994).
[17] C. Jamorski, M. E. Casida, and D. R. Salahub, J. Chem. Phys. 104, 5134 (1996).
[18] A. M. Köster, M. Krack, M. Leboeuf, B. Zimmermann, AllChem, Universität Hannover, 1998.
[19] deMon2k, Andreas M. Köster, Patrizia Calaminici, Mark E. Casida, Roberto Flores-Moreno, Gerald Geudtner, Annick Goursot, Thomas Heine, Andrei Ipatov, Florian Janetzko, Jorge M. del Campo, Serguei Patchkovskii, J. Ulises Reveles, Dennis R. Salahub, Alberto Vela, deMon developers, 2006.

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