Infra-red chemiluminescence II. Spectroscopic data

The technique described in part I has been used to obtain constants of interest in molecular spectroscopy. The vibration-rotation interaction factor, F for HCl has been evaluated from the infra-red emission spectrum. The critical parameter in F is θ = M 0 / M 1 r e , where M 0 and M 1 are the first two coefficients in the electric dipole moment expansion about the equilibrium internuclear distance r e . A value of θ = + 1.12 ± 0.18 has been obtained. It is shown that for molecules with θ = +1 the total band intensity in emission is independent of the rotational distribution in the vibrational state from which the emission occurs. This has been made use of in evaluating radiative transition probabilities. For the HCl v (3-1) transition a value for | R 3 1 | 2 (= 1.60 x 10 -4 debye 2 ) was obtained for the first time. The same method yields a value of | R 2 1 | 2 / | R 2 0 | 2 = 204, in good agreement with an earlier estimate from absorption data.

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An Investigation on the Fine Structure Levels in the Ground State Configuration for the Antimony Anion

Zeitschrift für Naturforschung A ◽

10.5560/zna.2014-0025 ◽

2014 ◽

Vol 69 (8-9) ◽

pp. 397-402

Author(s):

Leyla Özdemir ◽

Sadiye Tuna

Keyword(s):

Fine Structure ◽

Ground State ◽

Transition Probabilities ◽

Relativistic Effects ◽

Electric Quadrupole ◽

Radiative Transition ◽

Ground State Configuration ◽

Hartree Fock ◽

First Time ◽

State Configuration

We have investigated the correlation, relativistic, and isotope shift effects on the fine structure levels in the ground state configuration for the antimony anion ( Sb-). Energies and radiative transition probabilities (for magnetic dipole, M1, and electric quadrupole, E2) have been obtained using the multiconfiguration Hartree-Fock method within the framework of the Breit-Pauli Hamiltonian. Therefore, the most important configuration interaction and relativistic effects have been included. Comparisons with other available works are presented. For some M1 and E2 lines the considered transition probabilities are reported for the first time

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Benchmarking Current Capabilities for the Generation of Excitation and Photoionisation Atomic Data

Galaxies ◽

10.3390/galaxies6030090 ◽

2018 ◽

Vol 6 (3) ◽

pp. 90 ◽

Cited By ~ 1

Author(s):

Catherine Ramsbottom ◽

Connor Ballance ◽

Ryan Smyth ◽

Andrew Conroy ◽

Luis Fernández-Menchero ◽

...

Keyword(s):

Numerical Methods ◽

Cross Sections ◽

Transition Probabilities ◽

Energy Levels ◽

Radiative Transition ◽

Atomic Data ◽

High Quality ◽

Astronomical Instruments ◽

First Time ◽

Line Strengths

The spectra currently emerging from modern ground- and space-based astronomical instruments are of exceptionally high quality and resolution. To meaningfully analyse these spectra, researchers utilise complex modelling codes to replicate the observations. The main inputs to these codes are atomic data such as excitation and photoionisation cross sections, as well as radiative transition probabilities, energy levels, and line strengths. In this publication, the current capabilities of the numerical methods and computer packages used in the generation of these data are discussed. Particular emphasis is given to Fe-peak species and the heavy systems of tungsten and molybdenum. Some of the results presented to highlight certain issues and/or advances have already been published in the literature, while other sections present new recently evaluated atomic data for the first time.

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Measurement of the A-Value of the Intersystem Transition in Al II at 2670 Å: Å Progress Report

International Astronomical Union Colloquium ◽

10.1017/s0252921100085614 ◽

1984 ◽

Vol 86 ◽

pp. 163-166

Author(s):

B. Carol Johnson ◽

H.S. Kwong

Keyword(s):

Cross Sections ◽

Radiative Decay ◽

Transition Probabilities ◽

Radiative Transition ◽

Electron Excitation ◽

Spectral Lines ◽

Metastable Level ◽

Astrophysical Plasmas ◽

Atomic Ions ◽

A Value

Ratios of intensities of spectral lines produced in the radiative decay of collisionally-excited levels of atomic ions are versatile indicators of electron density in astrophysical plasmas when one of the lines involves a metastable level (see the review by Feldman 1981 and references therein). Radiative transition probabilities (A-values) and electron excitation cross sections are necessary for accurate, quantitative analyses of these plasmas. The work reported here is part of a program of measurements of astrophysically interesting A-values and radiative lifetimes (see the review by Smith et al. 1984); until we began, such anaylyses of astrophysical plasmas depended upon unconfirmed calculated A-values.

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Vibration-rotation bands of methyl fluoride

Proceedings of the Royal Society of London Series A - Mathematical and Physical Sciences ◽

10.1098/rspa.1954.0087 ◽

1954 ◽

Vol 222 (1151) ◽

pp. 443-455 ◽

Cited By ~ 15

Keyword(s):

Ground State ◽

Rotational Constant ◽

Microwave Spectrum ◽

Complete Analysis ◽

Methyl Fluoride ◽

A Value ◽

Infra Red ◽

Type Band ◽

Vibration Rotation

The vibration-rotation bands of methyl fluoride between 2⋅5 and 5 μ have been measured with higher resolution than previously. Three parallel bands have been analyzed, providing three independent values for B ", the rotational constant in the ground state. Each of these values is close to that obtained from the microwave spectrum (0⋅8518 cm -1 ), and some earlier values deduced from infra-red bands are shown to be incorrect. A value of 2⋅28 x 10 -6 cm -1 has also been obtained for D J , the centrifugal stretching constant, which is shown to be more satisfactory than that previously deduced from the microwave spectrum. A perpendicular type band has been resolved fairly completely, and it has been possible to measure the P and R lines of the sub-bands in addition to the strong Q branches. An analysis has been made which accounts satisfactorily for most of the lines in the entire band, and this provides the first example of such a complete analysis of a perpendicular band of a symmetrical top molecule.

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Benchmarking Current Capabilities for the Generation of Excitation and Photoionisation Atomic Data

10.20944/preprints201806.0412.v1 ◽

2018 ◽

Author(s):

Catherine Ramsbottom ◽

Connor Ballance ◽

Ryan Smyth ◽

Andrew Conroy ◽

Luis Fernández-Menchero ◽

...

Keyword(s):

Numerical Methods ◽

Cross Sections ◽

Transition Probabilities ◽

Energy Levels ◽

Radiative Transition ◽

Atomic Data ◽

High Quality ◽

Astronomical Instruments ◽

First Time ◽

Line Strengths

The spectra currently emerging from modern ground- and space-based astronomical instruments are of exceptionally high quality and resolution. To meaningfully analyse these spectra researchers utilise complex modelling codes to replicate the observations. The main inputs to these codes are atomic data such as excitation and photoionisation cross sections as well as radiative transition probabilities, energy levels and line strengths. In this publication the current capabilities of the numerical methods and computer packages used in the generation of these data are discussed. Particular emphasis is given to Fe-peak species and the heavy systems of tungsten and molybdenum. Some of the results presented to highlight certain issues and/or advances have already been published in the literature, while other sections present, for the first time, new recently evaluated atomic data.

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Radiative Transition Parameters in Atomic Lanthanum from Pseudo-Relativistic Hartree–Fock and Fully Relativistic Dirac–Hartree–Fock Calculations

Atoms ◽

10.3390/atoms7010038 ◽

2019 ◽

Vol 7 (1) ◽

pp. 38 ◽

Cited By ~ 2

Author(s):

Sébastien Gamrath ◽

Patrick Palmeri ◽

Pascal Quinet

Keyword(s):

Transition Probabilities ◽

Radiative Transition ◽

Physical Models ◽

Oscillator Strengths ◽

Mid Infrared ◽

Hartree Fock ◽

Near Ultraviolet ◽

First Time ◽

Theoretical Results

Calculated radiative transition probabilities and oscillator strengths are reported for 392 lines of neutral lanthanum (La I) atom in the spectral range from the near ultraviolet to the mid infrared. They were obtained using two different theoretical methods based on the pseudo-relativistic Hartree–Fock (HFR) and the fully relativistic multiconfiguration Dirac–Hartree–Fock (MCDHF) approaches, both including the most important intravalence and core-valence electron correlations. The quality of these radiative parameters was assessed through detailed comparisons between the results obtained using different physical models and between our theoretical results and the experimental data, where available. Of the total number of La I lines listed in the present work, about 60% have gf- and gA-values determined for the first time.

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The Measurement of Branching Ratios of Spontaneous Radiative Transition Probabilities for Be-Like Ions N IV and O V

International Astronomical Union Colloquium ◽

10.1017/s0252921100085493 ◽

1984 ◽

Vol 86 ◽

pp. 125-127

Author(s):

J. Lang ◽

R.A. Hardcastle ◽

P.H. Spurrett

Keyword(s):

Transition Probabilities ◽

Grazing Incidence ◽

Plasma Source ◽

Radiative Transition ◽

Branching Ratios ◽

Tungsten Filament ◽

Filament Lamp ◽

Line Intensities ◽

A Value ◽

Deuterium Lamp

In an experiment to measure emission line intensities from the Belike ion Ne VII (Lang 1983), the intensity ratio I(2s3s3S−2s3p3P)/I(2p23P−2s3p3P) was found to be a factor six larger than predicted from the ratio of the theoretical spontaneous radiative transition probabilities (A values). Indeed, to reconcile the Ne VII experiment and theory in several respects it was suggested also that in Be-like C III the theoretical ratios I(2s3s1 S−2s3p1P)/I(2p21D−2s3p1P) was about a factor three too low.The same apparatus was used to measure A value ratios in Be-like N IV and 0 V. Briefly the 40 kJ θ-pinch plasma source was viewed radially using a m Ebert and a l m grazing incidence photoelectric spectrometer. The m Ebert was intensity calibrated from 7300 Å to 3600 Å using a tungsten filament lamp, and from 3800 Å to 2500 Å using a deuterium lamp, both lamps having been calibrated by NPL. As described fully by Lang (1983), the branching-ratios method was used to calibrate the front exit slit of the grazing incidence instrument in the wavelength range 88 Å to 500 Å. Only Li-like line pairs of those listed in that paper were used with the addition of the C IV doublets 2s2S−3p2P (312.4 Å) and 3s2S−3p2P (5801.33 Å, 5811.98 Å). The H-like ion He II 1–4 transition (243.0 Å) and 3–4 transition (4685.7 Å) were used to cross-check the calibration. As shown in the figure, the He II result agrees excellently with the calibration as defined from the Li-like lines.

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New Transition and Energy Levels of Three-Times Ionized Krypton (Kr IV)

Atoms ◽

10.3390/atoms9030048 ◽

2021 ◽

Vol 9 (3) ◽

pp. 48

Author(s):

M. Raineri ◽

M. Gallardo ◽

J. Reyna Almandos ◽

A. G. Trigueiros ◽

C. J. B. Pagan

Keyword(s):

Transition Probabilities ◽

Energy Levels ◽

Pulsed Discharge ◽

Core Polarization ◽

Polarization Effects ◽

Hartree Fock ◽

Theta Pinch ◽

New Energy ◽

First Time

A capillary pulsed-discharge and a theta-pinch were used to record Kr spectra in the region of 330–4800 Å. A set of 168 transitions of these spectra were classified for the first time. We extended the analysis to twenty-five new energy levels belonging to 3s23p24d, 3s23p25d even configurations. We calculated weighted transition probabilities (gA) for all of the experimentally observed lines and lifetimes for new energy levels using a relativistic Hartree–Fock method, including core-polarization effects.

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