DALTON program

All the calculations have been carried out using a local version of the Dalton program package [26]. The implementation of the Cauchy moments for the CCS, CC2, and CCSD models has been described in Ref. [4]. The CC3 Cauchy moments have been implemented by us following the outline presented in the previous section. 

The selection of configuration state functions to be included in MCSCF calculations is not a trivial task. Two approaches which can reduce the complexity of the problem are the complete active space self-consistent-field (CASSCF) [68] and the restricted active space self-consistent-field (RASSCF) [69] approach. Both are implemented in the Dalton program package [57] and are used in this study. Throughout the paper a CASSCF calculation is denoted by i active gactive RASSCF calculation by For the active spaces of HF, H2O, and CH4... 

In the following, we will first present a formal derivation of the general PE equations rooted in intermolecular perturbation theory. Next follows a derivation of the PE scheme within the concepts of time-dependent density functional theory, and finally, we present a few illustrative examples. The PE model has been implemented in the Dalton program package [14]. 

The theory reviewed in this paper has recently been implemented in the 2.0 version of the Dalton program, available at http //www.kjemi.uio.no/software/ dalton/dalton.html. Tire authors acknowledge long time collaboration with their coauthors of tire Dalton program. In the area of density functional theory and applications Urey acknowledge in particular the collaboration with Professors Trygve Helgaker, Oslo, Kenneth Ruud, Tromsp, and Antonio Rizzo, Pisa. 

H.H), and from ca. 4 via 16 to 4 Hz for 0,0). The authors applied the MP2/aug-cc-pVTZ and B3LYP/HuzIVsu4 theory levels for geometry optimisation and coupling calculations, respectively. The calculations were carried out with GAMESS code and DALTON program. 

Tormena et have analysed the dependence of paramagnetic spin-orbit (PSO) and spin-dipolar (SD) terms oi J(F,F) on F-C-F bond angle in CF2H2. The authors predicted on the basis of qualitative analysis that isotropic J(F.F) coupling should depend on the relative orientation of the C-F bonds containing coupled nuclei and the eigenvectors of second-rank tensor of the PSO and SD contributions. This relationship was validated by the calculations at the SOPPA(CCSD)/EPR-in//MP2/EPR-III level with DALTON program. 

To quote from the authors of the program, the Dalton program system is designed to allow convenient, automated determination of a large number of molecular properties based on an HF, density functional theory (DFT), MP2, coupled cluster, or MCSCF reference wave function. Given the great flexibility of Dalton s computational capabilities, the authors describe it as... 

The most recent advances in ROA calculations include the implementation in the 09 version of GAUSSIAN of an analytical time-dependent protocol for the calculation of the ROA property-tensor derivatives, both HF and DFT, resulting in an order-of magnitude increase in speed of the calculations, even though the Dalton Program has included the ROA calculation as an option since 1997. Ab initio ROA calculations are complex, and a fiiU description of all methods available for calculating ROA spectra are beyond the scope of this chapter. Comprehensive descriptions of such methods for both resonance ROA and far-from resonance approximations may be found... 

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