Pseudopotentials for main group elements (IIIa through VIIa)

1,314

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.

Section: Application To Diatomic Moleculesmentioning

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

1,314

992

“…From a Taylor expansion of the cutoff function one can estimate that the new exponent ␦Ј for qϭ2 is related to the old exponent ␦ for qϭ1 by ␦ЈϾ␦ for small ␦, and a fit-procedure as described in Ref. 33 mdyn/Å͒ to 301.8 cm Ϫ1 ͑1.438 mdyn/Å͒ due to inclusion of CPP.…”

Section: ͑3͒mentioning

confidence: 99%

“…A subsequent paper will compare different pseudopotential approximations using a small core definition for indium. However, for the following we decided to adopt the simple SEFIT PP without CPP and CRC corrections, 33 which leads to satisfying results for all molecular properties due to error compensation.…”

Section: ͑3͒mentioning

confidence: 99%

See 1 more Smart Citation

The accuracy of the pseudopotential approximation. I. An analysis of the spectroscopic constants for the electronic ground states of InCl and InCl3 using various three valence electron pseudopotentials for indium

Schwerdtfeger

Fischer

Dolg

et al. 1995

Spectroscopic constants for InCl and InCl 3 are determined by a coupled cluster procedure using relatively large basis sets and an energy-consistent semilocal three valence electron pseudopotential for indium. Possible errors within the pseudopotential approximation are discussed in detail by comparison of available pseudopotentials adjusted through different techniques. Core-polarization corrections and the deviation from a point core approximation are discussed. These corrections, however, do not lead to more accurate bond distances as compared to the experimental results. Differently adjusted three valence electron pseudopotentials yield quite different results for the bond distances of InCl and InCl 3 . The single-electron adjusted energy-consistent pseudopotential of Igel-Mann et al. ͓Mol. Phys. 65, 1321 ͑1988͔͒ yields the best results and therefore, this pseudopotential has been chosen for all further investigations on molecular properties. The Dunham parameters for InCl are calculated by solving the vibrational-rotational Schrödinger equation numerically. A finite field technique is used to determine the dipole moment and dipole-polarizability of diatomic InCl. The dependence of several molecular properties on the vibrational quantum state is determined by calculating the expectation value P n ϭ͗n͉P(R)͉n͘, where P(R) is the distance dependent molecular property. The P(R) curves show strong linear behavior and therefore, the shape of the P n curve is mostly determined by anharmonicity effects in the InCl potential curve. For the vibrational ground state, ͉0͘, the calculated property P 0 deviates only slightly from the property determined directly at the equilibrium distance, P e . There is in general satisfying agreement of our calculated values with available experimental results. However, it is concluded that in order to obtain very accurate spectroscopic constants a small core definition for indium has to be preferred.

“…For Xe atoms, Stuttgart RLC ECP is employed. 10 As a preliminary calculation, the Xe-Xe potential energy curve is computed with this method. The equilibrium distance and binding energy are calculated to be r min …”

Section: A Ab Initio Calculationsmentioning

confidence: 99%

Competing effects of rare gas atoms in matrix isolation spectroscopy: A case study of vibrational shift of BeO in Xe and Ar matrices

Nakayama

Niimi

Ôno

et al. 2012

We investigate the vibrational shift of beryllium oxide (BeO) in Xe matrix as well as in Ar matrix environments by mixed quantum-classical simulation and examine the origin of spectral shift in details. BeO is known to form strong chemical complex with single rare gas atom, and it is predicted from the gas phase calculations that vibrational frequencies are blueshifted by 78 cm −1 and 80 cm −1 upon formation of XeBeO and ArBeO, respectively. When the effects of other surrounding rare gas atoms are included by Monte Carlo simulations, it is found that the vibrational frequencies are redshifted by 21 cm −1 and 8 cm −1 from the isolated XeBeO and ArBeO complexes, respectively. The vibrational shift of XeBeO in Ar matrix is also calculated and compared with experimental data. In all simulations examined in this paper, the calculated vibrational frequency shifts from the isolated BeO molecule are in reasonable agreement with experimental values. The spectral shift due to the rare-gas-complex formation of RgBeO (Rg = Xe or Ar) is not negligible as seen in the previous studies, but it is shown in this paper that the effects of other surrounding rare gas atoms should be carefully taken into account for quantitative description of the spectral shifts and that these two effects are competing in vibrational spectroscopy of BeO in matrix environments.