A b i n i t i o relativistic effective potentials with spin-orbit operators. II. K through Kr

Potential energy curves have been calculated for the ground and excited electronic states of KrH and the cation KrH ϩ by ab initio configuration interaction calculations using effective core potentials for Kr. Quantum defect functions have been determined from the ab initio potentials of the low-lying Rydberg states of KrH and potential energy curves have been generated for higher n (s,p,d) Rydberg states. The resulting bound-bound transition energies are in excellent agreement with experimental data. The interaction of the 5p B 2 ⌸ state with the 5s and 5p A 2 ⌺ and C 2 ⌺ ϩ states and their predissociation by X 2 ⌺ ϩ has been treated by multistate complex scaling calculations for both KrH and KrD. Much larger predissociation widths are obtained in KrH than in KrD, in agreement with experimental observations.

Section: A Ab Initio Calculationsmentioning

confidence: 99%

Theoretical ab initio study of the electronic states of KrH and KrH+: Quantum defect and complex coordinate calculations on the Rydberg states of KrH

Petsalakis

Theodorakopoulos

Buenker

2003

“…[23][24][25]), most recently by Dolg [26]. Several ECP families are available for the range of the periodic table of interest to us, such as the LANL (Los Alamos National Laboratory) ECPs of Hay and Wadt [27], the CEP (Consistent Effective Potential) family of Stevens, Basch, and coworkers [28], the Ermler-Christensen family [29], and the Stuttgart-Dresden-Bonn (SDB) energyconsistent pseudopotentials [30].…”

Section: Introduction and Theoretical Backgroundmentioning

confidence: 99%

Correlation consistent valence basis sets for use with the Stuttgart–Dresden–Bonn relativistic effective core potentials: The atoms Ga–Kr and In–Xe

Martin¹,

Sundermann²

2001

1,313

992

We propose large-core correlation-consistent pseudopotential basis sets for the heavy p-block elements Ga-Kr and In-Xe. The basis sets are of cc-pVTZ and cc-pVQZ quality, and have been optimized for use with the large-core (valence-electrons only) Stuttgart-Dresden-Bonn relativistic pseudopotentials.Validation calculations on a variety of third-row and fourth-row diatomics suggest them to be comparable in quality to the all-electron cc-pVTZ and cc-pVQZ basis sets for lighter elements. Especially the SDB-cc-pVQZ basis set in conjunction with a core polarization potential (CPP) yields excellent agreement with experiment for compounds of the later heavy p-block elements.For accurate calculations on Ga (and, to a lesser extent, Ge) compounds, explicit treatment of 13 valence electrons appears to be desirable, while it seems inevitable for In compounds. For Ga and Ge, we propose correlation consistent basis sets extended for (3d) correlation. For accurate calculations on organometallic complexes of interest to homogenous catalysis, we recommend a combination of the standard cc-pVTZ basis set for first-and second-row elements, the presently derived SDB-cc-pVTZ basis set for heavier p-block elements, and for transition metals, the small-core [6s5p3d] Stuttgart-Dresden 1 basis set-RECP combination supplemented by (2f 1g) functions with exponents given in the Appendix to the present paper.

“…The relativistic effective core potential of Hurley et al 57 was used, which replaces the 1s, 2s, 2p, 3s, 3p, and 3d electrons of Br. The basis set used was built on their 3s,3p set ͑contracted to 2s,2p͒.…”

Section: B Ab Initio Calculationsmentioning

confidence: 99%

The structure of alkali halide dimers: A critical test of ionic models and new ab initio results

Törring

Biermann

Hoeft

et al. 1996

The structure of alkali halide dimers: A critical test of ionic models and new ab initio results. T. Torring, S. Biermann, J. Hoeft, R. Mawhorter, R. J. Cave, and C. Szemenyei, J. Chem. Phys. 104, 8032 (1996) In semiempirical ionic models a number of adjustable parameters have to be fitted to experimental data of either monomer molecules or crystals. This leads to strong correlations between these constants and prevents a unique test and a clear physical interpretation of the fit parameters. Moreover, it is not clear whether these constants remain unchanged when the model is applied to dimers or larger clusters. It is shown that these correlations can be substantially reduced when reliable information about dimers is available from experiments or ab initio calculations. Starting with Dunham coefficients of the monomer potential determined from microwave measurements, we have calculated the monomer to dimer bond expansion and the bond angle without any additional adjustable parameter. Assuming that the overlap repulsion between nearest neighbors remains unchanged, the bond expansion is mainly determined by the simple Coulomb repulsion between equally charged ions and depends only very little on the effective ion polarizabilities. Deviation of the bond angle from 90°sensitively tests the difference of effective polarizabilities of the two ions. A comparison with previously available data and new ab initio MP2 results presented here for the heavy-atom containing dimers shows that bond angles can be modeled reasonably well with SeitzRuffa corrected Pauling polarizabilities while calculated bond expansions are much too long. This shows that changes of the overlap repulsion term must be considered for reliable predictions of the structure of dimers and larger clusters.