Hyperfine coupling constants for <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si7.gif" display="inline" overflow="scroll"><mml:mrow><mml:msubsup><mml:mrow><mml:mi mathvariant="normal">N</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow><mml:mrow><mml:mo>+</mml:mo></mml:mrow></mml:msubsup></mml:mrow></mml:math>, BO, AlO and GaO in rare gas matrices, using the polarizable continuum model

Grein, Friedrich

doi:10.1016/j.cplett.2005.10.079

Cited by 7 publications

(4 citation statements)

References 21 publications

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“…The experimental dielectric constants of Ne, Ar, and Kr matrices are 1.10, 1.75, and 1.85, respectively; therefore, the FC term for the Al center increases with the dielectric constant of the matrix. According to Grein’s theoretical explanation, , the large values for the FC term in Ar and Kr matrices result from the dominance of the Al 2+ O 2– configuration, which enhances the spin density at the Al center. Knight et al first used the CI method with the Dunning’s double-ζ with polarizations (DZP) basis set to evaluate the FC term for Al in AlO, and the result was in reasonable agreement with the experimental values.…”

Section: Results and Discussionmentioning

confidence: 99%

“…However, the determination of HFCCs for the CN and AlO molecules is a challenge for the computational approaches. The difficulties are that the unrestricted treatment for CN suffers from a large degree of spin contamination, and the delicate balance between the ionic states of AlO must be handled carefully in the electronic structure calculations. − Finally, to explore the performance of present approach for HFCC prediction of multiatomic organic radicals, we evaluate the HFCCs of vinyl (C 2 H 3 ) radical. We concomitantly address the following questions of technical interest: (i) Can HFCCs be accurately described by the active-space wave function?…”

Section: Introductionmentioning

confidence: 99%

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Toward Reliable Prediction of Hyperfine Coupling Constants Using Ab Initio Density Matrix Renormalization Group Method: Diatomic ²Σ and Vinyl Radicals as Test Cases

Lan

Kurashige

Yanai

2014

J. Chem. Theory Comput.

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The density matrix renormalization group (DMRG) method is used in conjunction with the complete active space (CAS) procedure, the CAS configuration interaction (CASCI), and the CAS self-consistent field (CASSCF) to evaluate hyperfine coupling constants (HFCCs) for a series of diatomic (2)Σ radicals (BO, CO(+), CN, and AlO) and vinyl (C2H3) radical. The electron correlation effects on the computed HFCC values were systematically investigated using various levels of active space, which were increasingly extended from single valence space to large-size model space entailing double valence and at least single polarization shells. In addition, the core correlation was treated by including the core orbitals in active space. Reasonably accurate results were obtained by the DMRG-CASSCF method involving orbital optimization, while DMRG-CASCI calculations with Hartree-Fock orbitals provided poor agreement of the HFCCs with the experimental values. To achieve further insights into the accuracy of HFCC calculations, the orbital contributions to the total spin density were analyzed at a given nucleus, which is directly related to the FC term and is numerically sensitive to the level of correlation treatment and basis sets. The convergence of calculated HFCCs with an increasing number of renormalized states was also assessed. This work serves as the first study on the performance of the ab initio DMRG method for HFCC prediction.

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Section: Results and Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Toward Reliable Prediction of Hyperfine Coupling Constants Using Ab Initio Density Matrix Renormalization Group Method: Diatomic ²Σ and Vinyl Radicals as Test Cases

Lan

Kurashige

Yanai

2014

J. Chem. Theory Comput.

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“…For example, Anderson and co-workers used mass spectrometry to investigate the oxidation of boron clusters and the subsequent reactions of the B n O m + cations with small molecules such as HF and H 2 O. Most of the available quantum chemical studies on boron oxides are for clusters containing up to three boron atoms. − For example, Drummond et al investigated the molecular structure and stability of a larger set of B n O m compounds, with m = 1−3 and n = 1−7, using molecular dynamics techniques in conjunction with plane-wave periodic density functional theory (DFT). Both gas-phase and solid bulk structures were considered.…”

Section: Introductionmentioning

confidence: 99%

Thermochemistry and Electronic Structure of Small Boron and Boron Oxide Clusters and Their Anions

et al. 2009

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Thermochemical properties of a set of small boron (B(n)) and boron oxide (B(n)O(m)) clusters, with n = 1-4 and m = 0-3, their anions, and the B(4)(2-) dianion, were calculated by using coupled-cluster theory CCSD(T) calculations with the aug-cc-pVnZ (n = D, T, Q, 5) basis sets extrapolated to the complete basis set limit with additional corrections. Enthalpies of formation, bond dissociation energies, singlet-triplet or doublet-quartet separation gaps, adiabatic electron affinities (EA), and both vertical electron attachment and detachment energies were evaluated. The predicted heats of formation show agreement close to the error bars of the literature results for boron oxides with the largest error for OBO. Our calculated adiabatic EAs are in good agreement with recent experiments: B (calc, 0.26 eV; exptl, 0.28 eV), B(2) (1.95, 1.80), B(3) (2.88, 2.820 +/- 0.020), B(4) (1.68, 1.60 +/- 0.10), BO (2.50, 2.51), BO(2) (4.48, 4.51), BOB (0.07), B(2)O(2) (0.37), B(3)O (2.05), B(3)O(2) (2.94, 2.94), B(4)O (2.58), and B(4)O(2) (3.14, 3.160 +/- 0.015). The BO bond is strong, so this moiety is maintained in most of the clusters. Thermochemical parameters of clusters are not linearly additive with respect to the number of B atoms. The EA tends to be larger in the dioxides. The growth mechanism of small boron oxides should be determined by a number of factors: (i) formation of BO bonds, (ii) when possible, formation of a cyclic B(3) or B(4), and (iii) combination of a boron cycle and a BO bond. When these factors compete, the strength of the BO bonds tends to compensate the destabilization arising from a loss of binding in the cyclic boron clusters, in such a way that a linear boron oxide prevails. When the B(2) moiety is present in these linear clusters, the oxide derivatives prefer a high spin state.

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“…Wang and co-workers used experimental photoelectron spectroscopy coupled with quantum chemical calculations to probe the electronic structures of small anions including B 3 O 2 − , B 4 O 2 − , B 4 O 3 − , and B 4 O 2 2− and their neutral counterparts. Most of the theoretical studies have focused on B n O m species with n as large as 5. – Recently, we predicted the enthalpies of formation and determined the electronic structures of a series of small B n O m compounds and their anions with n = 1−4 and m = 1−3 using high accuracy computational methods at the coupled-cluster theory CCSD(T) level with the correlation consistent aug-cc-pV n Z ( n = D, T, Q, 5) basis sets extrapolated to the complete basis set limits (CBS) with additional corrections . The calculated detachment energies are in good agreement with the available experimental data.…”

Section: Introductionmentioning

confidence: 99%

Thermochemical Properties and Electronic Structure of Boron Oxides B_nO_m (n = 5−10, m = 1−2) and Their Anions

2010

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The molecular and electronic structures of a series of small boron monoxide and dioxide clusters B(n)O(m) (n = 5-10, m = 1, 2) plus their anions were predicted. The enthalpies of formation (DeltaH(f)'s), electron affinities (EAs), vertical detachment energies, and energies of different fragmentation processes are predicted using the G3B3 method. The G3B3 results were benchmarked with respect to more accurate CCSD(T)/CBS values for n = 1-4 with average deviations of +/-1.5 kcal/mol for DeltaH(f)'s and +/-0.03 eV for EAs. The results extend previous observations on the growth mechanism for boron oxide clusters: (i) The low spin electronic state is consistently favored. (ii) The most stable structure of a neutral boron monoxide B(n)O is obtained either by condensing O on a BB edge of a B(n) cycle, or by binding one BO group to a B(n-1) ring. The balance between both factors is dependent on the inherent stability of the boron cycles. (iii) A boron dioxide is formed by incorporating the second O atom into the corresponding monoxide to form BO bonds. (iv) A B(n)O(m)(-) anion is constructed with BO groups bound to the B(n-1) or B(n-2) rings (yielding the B(n-2)(BO)(2)(-) species). This becomes the preferred geometry for the larger boron dioxides, even in the neutral state. The boronyl group mainly behaves as an electron-withdrawing substituent reducing the binding energy and resonance energy of the oxides. (v) The boron oxides conserve some of the properties of the parent boron clusters such as the planarity and multiple aromaticity.

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Hyperfine coupling constants for N2+, BO, AlO and GaO in rare gas matrices, using the polarizable continuum model

Cited by 7 publications

References 21 publications

Toward Reliable Prediction of Hyperfine Coupling Constants Using Ab Initio Density Matrix Renormalization Group Method: Diatomic ²Σ and Vinyl Radicals as Test Cases

Toward Reliable Prediction of Hyperfine Coupling Constants Using Ab Initio Density Matrix Renormalization Group Method: Diatomic ²Σ and Vinyl Radicals as Test Cases

Thermochemistry and Electronic Structure of Small Boron and Boron Oxide Clusters and Their Anions

Thermochemical Properties and Electronic Structure of Boron Oxides B_nO_m (n = 5−10, m = 1−2) and Their Anions

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Hyperfine coupling constants for N2+, BO, AlO and GaO in rare gas matrices, using the polarizable continuum model

Cited by 7 publications

References 21 publications

Toward Reliable Prediction of Hyperfine Coupling Constants Using Ab Initio Density Matrix Renormalization Group Method: Diatomic 2Σ and Vinyl Radicals as Test Cases

Toward Reliable Prediction of Hyperfine Coupling Constants Using Ab Initio Density Matrix Renormalization Group Method: Diatomic 2Σ and Vinyl Radicals as Test Cases

Thermochemistry and Electronic Structure of Small Boron and Boron Oxide Clusters and Their Anions

Thermochemical Properties and Electronic Structure of Boron Oxides BnOm (n = 5−10, m = 1−2) and Their Anions

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Toward Reliable Prediction of Hyperfine Coupling Constants Using Ab Initio Density Matrix Renormalization Group Method: Diatomic ²Σ and Vinyl Radicals as Test Cases

Toward Reliable Prediction of Hyperfine Coupling Constants Using Ab Initio Density Matrix Renormalization Group Method: Diatomic ²Σ and Vinyl Radicals as Test Cases

Thermochemical Properties and Electronic Structure of Boron Oxides B_nO_m (n = 5−10, m = 1−2) and Their Anions