Vacuo ultraviolet spectra of permanganate, pertechnetate and perrhenate

Mullen, P. A.; Schwochau, K.; J∅rgensen, Chr.Klixbüll

doi:10.1016/0009-2614(69)80017-5

Cited by 48 publications

(22 citation statements)

References 15 publications

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“…Finally, we draw attention to the MnO 4 − ion. The experimental spectrum 28 shows a strong absorption at 6.56 eV, but the associated transition has not been definitively assigned. Given the close agreement with one of our computed energies (6.54 eV), it is possible that this absorption may arise from the (1t 1 ) 2 → (2e) 2 double excitation (η = 2.113).…”

Section: Journal Of Chemical Theory and Computationmentioning

confidence: 94%

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Excitation Number: Characterizing Multiply Excited States

Barca

Gilbert

Gill

2017

J. Chem. Theory Comput.

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How many electrons are excited in an electronic transition? In this Letter, we introduce the excitation number η to answer this question when the initial and final states are each modeled by a single-determinant wave function. We show that calculated η values lie close to positive integers, leading to unambiguous assignments of the number of excited electrons. This contrasts with previous definitions of excitation quantities which can lead to mis-assignments. We consider several examples where η provides improved excited-state characterizations.

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Section: Journal Of Chemical Theory and Computationmentioning

confidence: 94%

“…“Exact” excitation energies are either experimental or accurate ab initio results. References − are denoted in the final column by superscript numbers.…”

mentioning

confidence: 99%

Excitation Number: Characterizing Multiply Excited States

Barca

Gilbert

Gill

2017

J. Chem. Theory Comput.

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“…On the experimental side, a number of studies on the UV−vis spectra of TcO 4 − and ReO 4 − have been reported. 77,83,84 Before discussing the two molecules and their spectra, we should emphasize that here we focus on a detailed analysis based on one specific snapshot. While we can thus analyze indirect and direct solvent effects in great detail, we lack the effect of dynamics, and the analysis should be viewed in this light.…”

Section: ∑ ∑mentioning

confidence: 99%

“…The (overlapping) bands are in the regions 32 300−38 700 cm −1 (∼4.0−4.8 eV) and 37 900− 43 500 cm −1 (∼4.7−5.4 eV) for TcO 4 − . 77,84 For ReO 4 − , the corresponding transitions are 40 300−46 000 cm −1 (∼5.0−5.7 eV) and 46 000−54 000 cm −1 (∼5.7−6.7 eV). 77,84 We see that our results are in reasonable agreement with these numbers.…”

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confidence: 99%

Relativistic Polarizable Embedding

Hedegård

Bast

Kongsted

et al. 2017

J. Chem. Theory Comput.

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Most chemistry, including chemistry where relativistic effects are important, occurs in an environment, and in many cases, this environment has a significant effect on the chemistry. In nonrelativistic quantum chemistry, a lot of progress has been achieved with respect to including environments such as a solvent or protein in the calculations, and now is the time to extend the possibilities for also doing this in relativistic quantum chemistry. The polarizable embedding (PE) model efficiently incorporates electrostatic effects of the environment by describing it as a collection of localized electric multipoles and polarizabilities obtained through quantum chemical calculations. In this article, we present the theory and implementation of four- and exact two-component Hamiltonians within a PE framework. We denote the methods the PE-4c-DFT and PE-X2C-DFT models. The models include a linear response formalism to calculate time-dependent (TD) properties: PE-TD-4c-DFT and PE-TD-X2C-DFT. With this first implementation, we calculate the PE-TD-4c-PBE0 excitation energies of the TcO and ReO ions in an explicit water solvent. This initial investigation focuses on the relative size of relativistic and solvent contributions to the excitation energies. The solvent effect is divided into an indirect solvent effect due to the structural perturbation of the XO ion and a direct electrostatic effect. The relativistic effects as well as both types of solvent effects are found to contribute to a shift in the excitation energies, but they do so to different extents depending on the ion and the electronic transition in question.

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“…It is not always clear when such difficulties will be encountered. One such case that is the subject of this study is the permanganate ion, MnO 4 À [13][14][15][16][17][18][19][20]. This d 0 complex is a very well investigated molecule in chemical research, across many different areas, going back as far as the 1930s [21,22].…”

Section: Introductionmentioning

confidence: 99%

Excited electronic states of MnO4−: Challenges for wavefunction and density functional response theories

Almeida¹,

McKinlay²,

Paterson³

2015

Chemical Physics

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a b s t r a c tThe lowest excited electronic states of the permanganate ion MnO 4 À are calculated using a hierarchy of coupled cluster response approaches, as well as time-dependent density functional theory. It is shown that while full linear response coupled cluster with singles and doubles (or higher) performs well, that permanganate represents a stern test for approximate coupled cluster response models, and that problems can be traced to very large orbital relaxation effects. TD-DFT is reasonably robust although errors around 0.6 eV are still observed. In order to further investigate the strong correlations prevalent in the electronic ground state large-scale RASSCF calculations were also performed. Again very large orbital relaxation in the correlated wavefunction is observed. Although the system can qualitatively be described by a single configuration, multi-reference diagnostic values show that care must be taken in this and similar metal complexes.

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Vacuo ultraviolet spectra of permanganate, pertechnetate and perrhenate

Cited by 48 publications

References 15 publications

Excitation Number: Characterizing Multiply Excited States

Excitation Number: Characterizing Multiply Excited States

Relativistic Polarizable Embedding

Excited electronic states of MnO4−: Challenges for wavefunction and density functional response theories

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