MOLPRO program

Several of the methods referred to in this chapter use the URCCSD(T) procedure in which a spin-unrestricted CCSD(T) calculation is performed on a high-spin RHF reference wavefunction, as implemented in the MOLPRO program. H. J. Werner, P. J. Knowles, R. D. Amos, A. Bemhardsson, A. Beming, P. Celani, D. 

CRYSCOR for describing correlation effects in periodic solids. This program essentially combines the accurate HF solution of the crystal structure problem in an atomic orbital (AO) representation available from the crystal code, with local correlation techniques, and, in particular, those implemented the molpro program of the Stuttgart group. 

Parameters of energy-consistent ab initio pseudopotentials and corresponding valence basis sets are available for almost all elements of the periodic table [93,94,117,190-192,194-201]. A compilation of parameters for the use within the MOLPRO program system also exists on the internet under the address http //www.theochem.uni-stuttgart.de. Special care has to be taken when spin-orbit coupling is included in calculations with small-core PPs some SO operators are constructed (similar to the large-core case) for a fully variational two-component treatment, whereas in some cases effective valence SO operators are defined. The latter have to be applied in SO-CI calculations for the valence electrons, in which the semi-core shells (outside the PP core) are frozen in their scalar-relativistic form. 

The simulations were carried out with the 6-31- -G(d) basis set [106-108] as well as with a more flexible mixed cc-pVDZ [109]/aug-cc-pVDZ [110] (for H/O atoms, respectively) basis set, hereafter referred to as apVDZ. The electronic structure calculations were carried out using the MOLPRO program package (version 2002.3) [111]. 

Closed-shell and restricted open-shell CCSD (RCC8D) and RCC8D(T) calculations were carried out with the MOLPRO programs [11, 12], using the cc-pVTZ basis set... 

Scheme 7.13 Cut through of the potential energy surfaces of benzene along the prefulvene mode—a vector from the Franck-Condon point to the Sj/Sq conical intersection— calculated using the MOLPRO program at the CASPT2 level with a (6,6) CAS space and a Roos ANO basis set truncated to 6-31G-quality Sj (black). So (red), Tj (green), and T2 (blue). Reprinted with permission from [28, 29]...

The use of distance criteria in the definition of the shape of the LWF domains and for controlling the level of the approximation is certainly not the only possibihty, even if it is the simplest one for instance, some topological index might be used instead, as is already possible in the MOLPRO program [116]. 

FIGURE 17.10 Excited states of BH calculated using a multi-configurational-self-consistent-field (MCSCF) complete-active-space method using the MOLPRO program, the state-of-the-art ... 

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