Ultrasound diagnostics in phlebology

Mendoza, Edgar Allan Villagómez; Schimmelpfennig, J.; Schimmelpfennig, L.

doi:10.12687/phleb-5-2015

Cited by 9 publications

(9 citation statements)

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“…A further simplification is introduced by neglecting all multicenter integrals. The atomic mean-field integrals are calculated with the AMFI program and then are transformed to a molecular orbital basis. These approximations introduce errors which are usually lower than 5%, even for purely organic molecules. , …”

Section: Methods and Computational Detailsmentioning

confidence: 99%

Mechanism of the Triplet-to-Singlet Upconversion in the Assistant Dopant ACRXTN

2016

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In this work, the photophysics of 3-(9,9-dimethylacridin-10(9H)-yl)-9H-xanthen-9-one (ACRXTN) has been investigated by combined density functional theory and multireference configuration interaction quantum chemical methods. ACRXTN was recently utilized as an assistant dopant in a green emitting organic light-emitting diode (OLED), increasing substantially the external electroluminescence quantum efficiency of the OLED. The efficient triplet-to-singlet upconversion, found experimentally in ARCXTN, cannot be explained solely on the basis of a small singlet–triplet energy gap. We find five interacting electronically excited states in a small energy interval: a charge-transfer excitation (triplet and singlet) from acridine to xanthone, a local xanthone triplet (ππ*) excitation, and a pair of triplet and singlet states originating from an nπ* excitation on xanthone. On the basis of calculated spin–orbit coupling constants and potential energy profiles, we propose here that the triplet (ππ*) state mediates the triplet-to-singlet upconversion in ACRXTN and that the carbonyl bond stretching motion plays an essential role in this process.

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Section: Methods and Computational Detailsmentioning

confidence: 99%

Mechanism of the Triplet-to-Singlet Upconversion in the Assistant Dopant ACRXTN

2016

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“…Such a one-center approximation is justified by the “short-sightedness” of the SO operator that acts mostly on the spherical core–shells. It leads to the atomic mean-field SO approximation (AMFSO), best known due to the widely distributed AMFI subroutines available at both Breit–Pauli and DKH1 levels . In this work we implement and test an AMFSO approach directly at X2C level within Turbomole.…”

Section: Theorymentioning

confidence: 99%

Density Functional Calculations of Electron Paramagnetic Resonance g- and Hyperfine-Coupling Tensors Using the Exact Two-Component (X2C) Transformation and Efficient Approximations to the Two-Electron Spin–Orbit Terms

Wodyński

Kaupp

2019

J. Phys. Chem. A

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A two-component quasirelativistic density functional theory implementation of the computation of hyperfine and g-tensors at exact two-component (X2C) and Douglas–Kroll–Hess method (DKH) levels in the Turbomole code is reported and tested for a series of smaller 3d1, 4d1, and 5d1 complexes, as well as for some larger 5d7 Ir and Pt systems in comparison with earlier four-component matrix–Dirac–Kohn–Sham results. A main emphasis is placed on efficient approximations to the two-electron spin–orbit contributions, comparing an existing implementation of two variants of Boettger’s “scaled nuclear spin–orbit” (SNSO) approximation in the code with a newly implemented atomic mean-field spin–orbit (AMFSO) approximation. The different variants perform overall comparably well with the four-component data. The AMFSO approximation has the added advantage of being able to include the spin–other–orbit contributions arising from the Gaunt term of relativistic electron–electron interactions. These are of comparably larger importance for the 3d complexes than for their heavier homologues. The excellent agreement between X2C and four-component electron paramagnetic resonance parameter results provides the opportunity to treat large systems efficiently and accurately with the computationally more expedient two-component quasirelativistic methodology.

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“…For the Pu atom and the plutonium molecules, SOC was treated a posteriori by state interactions between the MS-CASPT2 wave functions, using the restricted active space state interaction (RASSI) program, with spin–orbit integrals computed in the atomic mean field approximation using the AMFI code. , These results are referred to as SO-CASPT2. The SOC contributions to the ground-state energies, i.e.…”

Section: Computational Detailsmentioning

confidence: 99%

Accurate Predictions of Volatile Plutonium Thermodynamic Properties

et al. 2019

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Having the ability to predict the nature and amounts of plutonium emissions in industrial accidents, such as in solvent fires at PUREX nuclear reprocessing facilities, is a key concern of nuclear safety agencies. In accident conditions and in the presence of oxygen and water vapor, plutonium is expected to form three major volatile species PuO2, PuO3, and PuO2(OH)2, for which the thermodynamic data necessary for predictions (enthalpies of formation and heat capacities) presently shows either large uncertainties or is lacking. In this work we aim to alleviate such shortcomings by obtaining the aforementioned data via relativistic correlated electronic structure calculations employing the Multi-State Complete Active Space with Second-Order Perturbation Theory (MS-CASPT2) with state-interaction RASSI spin-orbit coupling approach, which is able to describe the multireference character of the ground-state wavefunctions of PuO3 and PuO2(OH2). We benchmark this approach by comparing it to relativistic coupled cluster calculations for the ground, ionized and excited states of PuO2. Our results allow us to predict enthalpies of formation ∆ f H − • (298.15 K) of PuO2, PuO3 and PuO2(OH)2 to be (−449.5 ± 8.3) kJ mol −1 , (−553.2 ± 27.3) kJ mol −1 , and (−1012.6 ± 38.0) kJ mol −1 , respectively, which confirm the predominance of plutonium dioxide, but also reveal the existence of plutonium trioxide in gaseous phase under oxidative condition, though the partial pressures of PuO3 and PuO2(OH)2 are nonetheless always rather low under wet atmosphere. Our calculations also permit us to reassess prior results for PuO2, establishing the ground state of the PuO2 molecule is mainly of 5 Σ + g character, as well as to confirm the experimental value for the adiabatic ionization energy of PuO2.

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Ultrasound diagnostics in phlebology

Cited by 9 publications

References 0 publications

Mechanism of the Triplet-to-Singlet Upconversion in the Assistant Dopant ACRXTN

Mechanism of the Triplet-to-Singlet Upconversion in the Assistant Dopant ACRXTN

Density Functional Calculations of Electron Paramagnetic Resonance g- and Hyperfine-Coupling Tensors Using the Exact Two-Component (X2C) Transformation and Efficient Approximations to the Two-Electron Spin–Orbit Terms

Accurate Predictions of Volatile Plutonium Thermodynamic Properties

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