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We studied the role of intrinsic defects of matrix and Bi dopant in the formation of optical properties and energy structure of CaMoO 4 :Bi ceramic. Non-elementary luminescence was detected in a pure CaMoO 4 matrix due to radiative transitions in intrinsic vacancy-type defects, which are associated with non-stoichiometry in calcium. The experiment showed that Bi ions act as quenchers of luminescence. © Published under licence by IOP Publishing Ltd.

We have presented an effective relativistic approach for sensing and calculating energy of levels, probabilities and oscillator strengths (transition amplitudes, lifetimes) of a number of radiative transitions in the spectra of heavy Rydberg atoms of alkaline elements. It represents a new version of the relativistic model potential method. The approach is based on the relativistic many-body gauge-invariant perturbation theory with the improved Dirac-Kohn-Sham zeroth approximation and relativistic energy approach (S-matrix adiabatic Gell-Mann and Low formalism). We have shown that that during computing the energy and spectroscopic characteristics of the multielectron Rydberg atomic systems a new approach provides a precise accounting exchange-correlation effects, including effect of essentially non-Coulomb grouping of Rydberg levels, pressure continuum. There are received precise data on energy and spectroscopic parameters energy, radiation width, amplitude transitions, the lifetime) for Rydberg atoms Rb, Cs, Fr, particularly, transitions nS½→n’P½,3/2 (n=5,6; n’=10-70), nP½,3.2→n’D3/2,5/2 (n=5,6; n’=10-80) in the Rb, Cs spectra; for Rydberg Fr there are in most first calculated and predicted spectroscopic data on transition amplitude, lifetime of Rydberg states and transitions 7S½-nP½,3/2, 7P½,3.2-nD3/2,5/2 (n=20-80). Regarding the application of the obtained data it can be indicated on carrying out new types of radiative quantum sensors and frequency standards, quantum electronics and different quantum devices., Ми запропонували ефективний релятивістський підхід до детектування та розрахунку енергій рівнів, ймовірностей і сил осциляторів (амплітуд переходів, часів життя) ряду радіаційних переходів в спектрах важких рідбергівських атомів лужних елементів. Він являє собою версію моделі релятивістської потенційного методу. Підхід заснований на релятивістській багаточастинковій калібрувально-інваріантній теорії збурень з покращеним Дірак-Кона-Шемівським нульовим наближенням і релятивістському енергетичному формалізмі (S-матричний адіабатичний формалізм Гелл-Манн і Лоу). Показано, що підхід забезпечує досить ефективний ступінь урахування обмінно-кореляційних ефектів, у тому числі ефекту істотно некулонівського групування рідбергівських рівнів, тиску континууму і т.і. Отримано уточнені дані по енергетичним і спектроскопічним параметрам (енергії, радіаційні ширини, амплітуди переходів, час життя) для рідбергівських атомів Rb, Cs, Fr, зокрема, переходів nS½→n’P½,3/2 (n=5,6; n’=10-70), nP½,3.2→n’D3/2,5/2 (n=5,6; n’=10-80) в спектрах Rb, Cs; для рідбергівського Fr розраховані і передбачені спектроскопічні дані по амплітудах переходів, часам життя рідбергівських станів і переходів 7S½-nP½,3/2, 7P½,3.2-nD3/2,5/2 (n=20-80). Стосовно застосувань отриманих даних слід указати на можливості побудови нових типів радіаційних квантових сенсорів і квантових стандартів частоти, а також застосування в галузях квантової електроніки і фізики квантових пристроїв., Выполнен расчет вероятностей и сил осцилляторов ряда радиационных переходов в спектрах тяжелых ридберговских атомов щелочных элементов на основе нового релятивистского метода модельного потенциала в рамках калибровочно-инвариантной теории возмущений и релятивистского энергетического подхода. Показано, что подход обеспечивает достаточно эффективный учет обменно-корреляционных эффектов, в том числе эффекта существенно некулоновского группирования ридберговских уровней, давления континуума и т.д. Получены уточненные данные по энергетическим и спектроскопическим параметрам (энергии, радиационные ширины, амплитуды переходов, время жизни) для ридберговских атомов Rb, Cs, Fr, в частности, переходы nS½→n’P½,3/2 (n=5,6; n’=10-70), nP½,3.2→n’D3/2,5/2 (n=5,6; n’=10-80) в спектрах Rb, Cs; для ридбергского Fr рассчитаны и предсказаны спектроскопические данные по амплитудам переходов, временам жизни ридберговских состояний и переходов 7S½-nP½,3/2, 7P½,3.2-nD3/2,5/2 (n=20-80). Полученные данные могут быть использованы при создании новых типов радиационных квантовых сенсоров и стандартов частоты.

Electronic transitions from one excited state to another excited state of different spin symmetry play important roles in many biochemical reactions. Although recent years have seen much progress in the elucidation of nonradiative (intersystem crossing) relaxation mechanisms for such transitions, there is presently a scarcity of data available to assess whether also radiative (phosphorescence) mechanisms are relevant for these processes. Here, we demonstrate that the well-established ability of quantum chemical methods to describe intersystem crossing events between excited states can be supplemented by the ability to also describe inter-excited-state phosphorescence. Specifically, by performing four-component relativistic time-dependent density functional theory calculations, we obtain rate constants for the radiative transitions from the absorbing 1(πHπL∗) singlet state of lumiflavin to the 3(πHπL∗), 3(nN2πL∗), and 3(πH-1πL∗) triplet states, and subsequently, we compare these results with rate constants calculated for the corresponding nonradiative transitions. Thereby, it is found that the radiative rate constants for these particular transitions are typically 2 to 5 orders of magnitude smaller than the nonradiative ones., QC 20170118

Electronic transitions from one excited state to another excited state of different spin symmetry play important roles in many biochemical reactions. Although recent years have seen much progress in the elucidation of nonradiative (intersystem crossing) relaxation mechanisms for such transitions, there is presently a scarcity of data available to assess whether also radiative (phosphorescence) mechanisms are relevant for these processes. Here, we demonstrate that the well-established ability of quantum chemical methods to describe intersystem crossing events between excited states, can be supplemented by the ability to also describe inter-excited state phosphorescence. Specifically, performing four-component relativistic time-dependent density functional theory calculations, we obtain rate constants for the radiative transitions from the absorbing 1(πHπL*) singlet state of lumiflavin to the 3(πHπL*), 3(nN2πL*) and 3(πH–1πL*) triplet states, and subsequently compare these results with rate constants calculated for the corresponding nonradiative transitions. Thereby, it is found that the radiative rate constants for these particular transitions are typically two to five orders of magnitude smaller than the nonradiative ones., Vid tiden för disputation förelåg publikationen som manuskript

This document is the Final Technical Report for the PETTT Special Project BY09-012SP, Enhanced Computational Toolbox Including Multiquantum Vibration-Translation (VT) & Vibration-Electronic (VE) Exchanges, Dissociation and Radiation Effects. This project involved producing a computational toolbox for implementation of master equation based on detailed state-to-state (STS) kinetics. A toolbox has been developed to account for Vibration-translation (VT), Vibration-Electronic (VE), radiative transitions and state specific dissociation, based on nitrogen molecules (and atoms). The deliverable is in a modular form which can be interfaced with other related codes at AFRL to improve their prediction capabilities for accurate design and analysis of hypersonic vehicle trajectories. Accurate simulation of space vehicle trajectories requires high fidelity computational tools capable of describing complex multiphysics and nonequilibrium phenomena (present in the flow fields) especially due to translational, rotational, vibrational, ionization, dissociation, recombination and radiative modes. This toolbox facilitates the users to investigate and identify the dominant physical/chemical/electronic/other mechanisms particular to a problem and rapidly implement and evaluate new models as required. Using operator splitting algorithms, separate code modules for treatment of flow and treatment of STS kinetics were created. The code module for treatment of state-to-state kinetics may also be used as a standalone code for study of spatially homogenous (or zero-dimensional) flows, for a range of flow parameters. The enhanced toolbox is the primary project deliverable., The original document contains color images. Sponsored in part by Air Force Research Laboratory, Wright-Patterson AFB, OH, and the Air Force Office of Scientific Research.

Reliable atomic data have been computed for the spectral modeling of the nitrogen K lines, which may lead to useful astrophysical diagnostics. Data sets comprise valence and K-vacancy level energies, wavelengths, Einstein A-coefficients, radiative and Auger widths, and K-edge photoionization cross sections. An important issue is the lack of measurements that are usually employed to fine-tune calculations so as to attain spectroscopic accuracy. In order to estimate data quality, several atomic structure codes are used and extensive comparisons with previous theoretical data have been carried out. In the calculation of K photoabsorption with the Breit-Pauli R-matrix method, both radiation and Auger dampings, which cause the smearing of the K edge, are taken into account. This work is part of a wider project to compute atomic data in the X-ray regime to be included in the database of the popular XSTAR modeling code.

Reliable atomic data have been computed for the spectral modeling of the nitrogen K lines, which may lead to useful astrophysical diagnostics. Data sets comprise valence and K-vacancy level energies, wavelengths, Einstein A-coefficients, radiative and Auger widths, and K-edge photoionization cross sections. An important issue is the lack of measurements that are usually employed to fine-tune calculations so as to attain spectroscopic accuracy. In order to estimate data quality, several atomic structure codes are used and extensive comparisons with previous theoretical data have been carried out. In the calculation of K photoabsorption with the Breit-Pauli R-matrix method, both radiation and Auger dampings, which cause the smearing of the K edge, are taken into account. This work is part of a wider project to compute atomic data in the X-ray regime to be included in the database of the popular XSTAR modeling code.

Quantum mechanical and semiclassical approaches are discussed for the study of molecular collisions in an intense laser field. Both a coherent state and Fock state representation of the photon field are investigated. The collision dynamics is described in terms of transitions between two electronic-field potential energy surfaces, where each surface depends on the field-free adiabatic surfaces and electric dipole transition matrix elements as functions of nuclear coordinates. The electronic-field surfaces exhibit avoided crossings (on the real axis) due to the radiative coupling at the resonance nuclear configurations, and other parts of these surfaces are similar to the field-free adiabatic surfaces with one of them shifted by h bar omega for single photon processes. Metastable states, formed at some collision energies, are conjectured to occur in the field, although absent from the field free case. From a spectroscopic point of view, changes in energy spectra are expected from those of the individual collision-free species. Numerical results are presented for the collinear collision process Br(2P3/2) + H2(v = 0) + h bar omega Br(2P1/2) + H2(v = 0). Author), Reprinted from Faraday Discussions of the Chemical Society, n62 p247-254 1977.