MRCI multi-reference configuration

MRCI multi-reference configuration /nteraction. Cl based on an MCSCF calcula-... 

MRCI, multi-reference configuration interaction pseudopotential calculations. 

ACPF = averaged CPF ANO = atomic natural orbital CCSD(T) = singles and doubles coupled-cluster approach with a perturbational estimate of the triples excitation Cl = configuration interaction CPF = coupled pair functional CPP = core polarization potential CVCI = core-valence Cl FCI = full configuration interaction ICACPF = internally contracted ACPF ICMRCI = internally contracted MRCI MCPF = modified CPF MRCI = multi-reference configuration interaction NHF = numeric Hartree-Fock SDCI = singles plus doubles Cl. 

To answer this, we calculated the PES s by the ab initio MRCI (multi-reference configuration interaction) method (8). In order to describe the low-lying electronic states accurately, the active space was selected as follows [(9a)(2ic)(37i)(47c)(10a)(l lc)Y ... 

Structures were optimized at the theoretical level described in Table 1, footnote a. Final energies were obtained by using multi-reference configuration interaction (MRCI) wave functions including single and double excitations from die reference wave functions. cFrom Reference 8. 

Werner and co-workers [2, 21, 34] used internally-contracted multi-reference configuration-interaction (IC-MRCI) calculations, based on state-averaged (three-state) multi-configuration, self-consistent-field (MCSCF) calculations with large atomic orbital basis sets, to determine the three electronically adiabatic C1(F)+H2 PESs in the reactant arrangement L4, 2A, and lA. These all correlate with X( P) + H2. These three adiabatic electronic states are the IC-MRCI approximations to the three lowest eigenfunctions of Hgi, namely... 

Fig. 19.8. Differences between the isotropic Compton profile computed from theory and various experiments. The theoretical data is from a multi-reference configuration interaction (MRCI) calculation in a (5s5p4d3f) basis set of Slater-type functions [104]. Experimental data (+), 25 keV electron impact at 12° [109] ( ), average of Ag Ka and Mo Ka X-ray scattering [108,105] ( ), 160 keV y-ray scattering [105] (O), 160 keV y ray scattering reanalyzed [105,106] (A), 60keV y-ray scattering [107]. The dotted lines enclose the band of uncertainty in the experimental data.

Ref. [104]. r is a (5s5p4d3f) basis set of Slater-type functions. SCF is self-consistent field, MRCI is multi-reference configuration interaction. 

Figure 2.31 Experimental and multi-reference configuration interaction (MRCI ...

Our group has already studied all the fluoro-, chloro-and bromo-carbenes [11-16]. We used the complete active space self-consistent field (CASSCF) method as well as complete active space second-order perturbation theory (CASPT2) and multi-reference configuration interaction (MRCI) approaches to compute the geometries, force constants, and vibrational frequencies of the (singlet) X and A states as well as the (triplet) a states. Our theoretical studies of most of these carbenes were carried out specifically to complement LIF studies that were pursued in our laboratories by Kable et al. [6]. In addition to the determination of spectroscopic constants, the spectroscopic and theoretical studies considered dynamics on the A surfaces, i.e. whether photodissociation or internal conversion to the ground state would occur. 

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