Excitation energies and oscillator strengths of Ca I using multireference many-body perturbation theory

1999 ◽  
Vol 59 (5) ◽  
pp. 3432-3439 ◽  
Author(s):  
Sonjoy Majumder ◽  
B. P. Das ◽  
Rajat K. Chaudhuri
Keyword(s):  
Perturbation Theory ◽  
Oscillator Strengths ◽  
Many Body ◽  
Excitation Energies ◽  
Many Body Perturbation Theory

Excitation energies with multireference many‐body perturbation theory

1990 ◽  
Vol 93 (3) ◽  
pp. 1847-1856 ◽  
Author(s):  
Leszek Meissner ◽  
Stanislaw A. Kucharski ◽  
Rodney J. Bartlett
Keyword(s):  
Perturbation Theory ◽  
Many Body ◽  
Excitation Energies ◽  
Many Body Perturbation Theory

scholarly journals RELATIVISTIC CALCULATION OF WAVELENGTHS AND E1 OSCILLATOR STRENGTHS IN Li-LIKE MULTICHARGED IONS AND GAUGE INVARIANCE PRINCIPLE

2021 ◽  
pp. 134-142
Author(s):  
O. Khetselius ◽  
A. Mykhailov
Keyword(s):  
Perturbation Theory ◽  
Invariance Principle ◽  
Gauge Invariance ◽  
Oscillator Strengths ◽  
Relativistic Energy ◽  
Many Body ◽  
Zeroth Order ◽  
Many Body Perturbation Theory ◽  
Precise Experiment ◽  
Particle Approximation

The spectral wavelengths and oscillator strengths for 1s22s (2S1/2) → 1s23p (2P1/2) transitions in the Li-like multicharged ions with the nuclear charge Z=28,30 are calculated on the basis of the combined relativistic energy approach and relativistic many-body perturbation theory with the zeroth order optimized Dirac-Kohn-Sham one-particle approximation  and gauge invariance principle performance. The comparison of the obtained results with available theoretical and experimental (compilated) data is performed. The important point is linked with an accurate accounting for the complex exchange-correlation (polarization) effect contributions and using the optimized one-quasiparticle representation in the relativistic many-body perturbation theory zeroth order that significantly provides a physically reasonable agreement between theory and precise experiment.

scholarly journals Exciton Modulation in Perylene-Based Molecular Crystals Upon Formation of a Metal-Organic Interface From Many-Body Perturbation Theory

2021 ◽  
Vol 9 ◽  
Author(s):  
Liran Shunak ◽  
Olugbenga Adeniran ◽  
Guy Voscoboynik ◽  
Zhen-Fei Liu ◽  
Sivan Refaely-Abramson
Keyword(s):  
Perturbation Theory ◽  
Crystal Packing ◽  
Molecular Crystals ◽  
Gold Surface ◽  
Structure Property ◽  
Many Body ◽  
Excitation Energies ◽  
Interface Composition ◽  
Many Body Perturbation Theory ◽  
Metal Organic

Excited-state processes at organic-inorganic interfaces consisting of molecular crystals are essential in energy conversion applications. While advances in experimental methods allow direct observation and detection of exciton transfer across such junctions, a detailed understanding of the underlying excitonic properties due to crystal packing and interface structure is still largely lacking. In this work, we use many-body perturbation theory to study structure-property relations of excitons in molecular crystals upon adsorption on a gold surface. We explore the case of the experimentally-studied octyl perylene diimide (C8-PDI) as a prototypical system, and use the GW and Bethe-Salpeter equation (BSE) approach to quantify the change in quasiparticle and exciton properties due to intermolecular and substrate screening. Our findings provide a close inspection of both local and environmental structural effects dominating the excitation energies and the exciton binding and nature, as well as their modulation upon the metal-organic interface composition.

Relativistic many-body calculations of excitation energies, line strengths, transition rates, and oscillator strengths in Pd-like ions

2005 ◽  
Vol 83 (8) ◽  
pp. 813-828 ◽  
Author(s):  
U I Safronova ◽  
T E Cowan ◽  
W R Johnson
Keyword(s):  
Perturbation Theory ◽  
Transition Probabilities ◽  
Second Order ◽  
Oscillator Strengths ◽  
Transition Rates ◽  
Matrix Elements ◽  
Coupling Coefficients ◽  
Many Body ◽  
Excitation Energies ◽  
Line Strengths

Excitation energies, line strengths, oscillator strengths, and transition probabilities are calculated for 4d–14f, 4d–15p, 4d–15f, and 4d–16p hole–particle states in Pd-like ions with nuclear charges Z ranging from 49 to 100. Relativistic many-body perturbation theory (MBPT), including the Breit interaction, is used to evaluate retarded E1 matrix elements in length and velocity forms. The calculations start from a [Kr] 4d10 closed-shell Dirac–Hartree–Fock (DHF) potential and include second- and third-order Coulomb corrections and second-order Breit–Coulomb corrections. First-order perturbation theory is used to obtain intermediate-coupling coefficients and second-order MBPT is used to determine matrix elements. Contributions from negative-energy states are included in the second-order electric-dipole matrix elements. The resulting transition energies, line strengths, and transition rates are compared with experimental values and with other recent calculations. Trends of oscillator strengths as functions of nuclear charge Z are shown graphically for all transitions from the 4d–14f, 4d–15p, 4d–15f, and 4d–16p states to the ground state. PACS Nos.: 31.15.Ar, 31.15.Md, 32.70.Cs, 32.30.Rj, 31.25.Jf

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