MOLCAS program package

Table 14.3 Computation times (in seconds) of various exact-decoupiing methods for the heavy ion Rn+ . m denotes the number of basis functions. Time ratios with respect to m=100 are given in parentheses. The data have been taken from Ret. [16], which describes the implementation in the Molcas program package [638], The results were obtained tor 128-bit precision on an Opteron 250 central processing unit. The evaluation of one-electron integrals was not included in the measurement of the computing time.

Karlstrom G, Lindh R, Malmqvist P-A, Roos B, Ryde U, Veryazov V, Widmark P-O, Cossi M, Schimmelpfennig B, Neogrady P, Seijo L (2003) Molcas a program package for computational chemistry. Comput material sci 28 222... 

Hamiltonian resulting from the Douglas-Kroll transformation is particularly indicated for heavy elements and in variational calculations, because it is bounded from below (Samzow et al. 1992). The raw integrals are by now combined with AO and MO information from a variety of standard program packages (Molecule-Sweden, Columbus, Turbomole) and SOMF integrals are provided for BnSoc, Columbus, Molcas and LuciaRel. 

M. Cossi, B. Schimmelpfennig, P. Neogrady, and L. Seijo, Computat. Mater. Sci., 28, 222 (2003). Molcas a Program Package for Computational Chemistry. 

Several different versions of second-order perturbation theory for multireference wave functions have been implemented but the one currently in widest use is probably the CASPT2 method. This method was developed by Roos and co-workers in Lund, Sweden, and it is available in their MOLCAS package of computer programs. 

Implementations of the spin-free DKH Hamiltonian exist by now for many standard quantum chemistry packages like Molecule-Sweden, Columbus, Turbomole, Molcas and Nwchem. The method has also been implemented in several programs for the calculation of periodic structures, in particular crystals (Boettger 1998b Fehrenbach and Schmidt 1997 Geipel and Hess 1997). 

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