Excitation energies, radiative and autoionization rates, dielectronic satellite lines and dielectronic recombination rates for excited states of Ag-like W from Pd-like W

We calculate energy levels, radiative transition probabilities, and autoionization rates for Be-like oxygen (O4+) including 1s2 2lnl' (n = 28, l [Formula: see text] n 1) and 1s23l' nl (n = 36, l [Formula: see text] n 1) states by the multiconfigurational HartreeFock method (Cowan code) and the perturbation theory Z-expansion method (MZ code). The state selective dielectronic recombination-rate coefficients to excited states of Be-like oxygen are obtained, which are useful for modeling O V spectral lines in a recombining plasma. Configuration mixing plays an important role for the principal quantum number, n, distribution of the dielectronic recombination-rate coefficients for 2snl (n [Formula: see text] 5) levels at low electron temperature. The orbital angular momentum quantum number, l, distribution of the rate coefficients shows a peak at l = 4. The total dielectronic recombination-rate coefficient is derived as a function of electron temperature. The dielectronic satellite lines are also obtained. PACS Nos.: 34.80Lx, 32.80Dz, 32.30Jc, 31.10+z

Download Full-text

Dielectronic recombination rates to the n = 3 singly excited states: The neon sequence

Journal of Quantitative Spectroscopy and Radiative Transfer ◽

10.1016/0022-4073(95)00106-u ◽

1995 ◽

Vol 54 (4) ◽

pp. 737-743 ◽

Cited By ~ 1

Author(s):

Arati Dasgupta

Keyword(s):

Excited States ◽

Dielectronic Recombination ◽

Recombination Rates

Download Full-text

Exploitation of Baird Aromaticity and Clar’s Rule for Tuning the Triplet Energies of Polycyclic Aromatic Hydrocarbons

Chemistry ◽

10.3390/chemistry3020038 ◽

2021 ◽

Vol 3 (2) ◽

pp. 532-549

Author(s):

Felix Plasser

Keyword(s):

Polycyclic Aromatic Hydrocarbons ◽

Excited States ◽

Aromatic Hydrocarbons ◽

Density Functional ◽

Materials Science ◽

Chemical Shifts ◽

Qualitative Description ◽

Triplet States ◽

Excitation Energies ◽

Polycyclic Aromatic

Polycyclic aromatic hydrocarbons (PAH) are a prominent substance class with a variety of applications in molecular materials science. Their electronic properties crucially depend on the bond topology in ways that are often highly non-intuitive. Here, we study, using density functional theory, the triplet states of four biphenylene-derived PAHs finding dramatically different triplet excitation energies for closely related isomeric structures. These differences are rationalised using a qualitative description of Clar sextets and Baird quartets, quantified in terms of nucleus independent chemical shifts, and represented graphically through a recently developed method for visualising chemical shielding tensors (VIST). The results are further interpreted in terms of a 2D rigid rotor model of aromaticity and through an analysis of the natural transition orbitals involved in the triplet excited states showing good consistency between the different viewpoints. We believe that this work constitutes an important step in consolidating these varying viewpoints of electronically excited states.

Download Full-text

Modification of HAM/3 excitation energies for ΠΠ* transitions of linear molecules

Canadian Journal of Chemistry ◽

10.1139/v80-270 ◽

1980 ◽

Vol 58 (16) ◽

pp. 1687-1690 ◽

Cited By ~ 8

Author(s):

Delano P. Chong

Keyword(s):

Excitation Energy ◽

Explicit Expression ◽

Excited States ◽

Configuration Interaction ◽

Excitation Energies ◽

Carbon Suboxide ◽

Numerical Examples ◽

Energy Correction ◽

Linear Molecules ◽

Configuration Interaction Calculations

The excitation energies calculated by the HAM/3 procedure for ΠΠ* transitions in linear molecules can be internally inconsistent by as much as ± 0.6 eV. In the recent study by Åsbrink etal., the problem was avoided by adopting Recknagel's expressions and requiring the proper average ΠΠ* excitation energy. In this paper, we trace the small inconsistency back to its origin in HAM/3 theory and derive the analytical expression for the energy correction as well as Recknagel's formulas. Numerical examples studied include all seven linear molecules investigated by Åsbrink etal. The explicit expression for the correction enables us to perform meaningful configuration-interaction calculations on the excited states, as illustrated by the carbon suboxide molecule.

Download Full-text