Measurement of oscillator strengths of the MgO(B1Σ+ - X1Σ+) and MgH(A2π - X2Σ+) band systems

doi:10.1016/0022-4073(67)90036-2

Journal of Quantitative Spectroscopy and Radiative Transfer

Volume 7, Issue 5, September–October 1967, Pages 805-811

https://doi.org/10.1016/0022-4073(67)90036-2 Get rights and content

Abstract

Absolute emission intensities of a portion of the flame at the exit plane of a rocket engine burning hydrogen, fluorine, and a slurry of powdered MgO in water were measured. From these measurements and thermochemical calculations we have found an ƒ-value for the MgO(B¹Σ⁺ - X¹Σ⁺) band system of $ƒ_{el} ≅ƒ_{Δv=0} = (1·3±0·5) x 10^{-3}$ . For the MgH(A²π-X²Σ⁺) band system we find $ƒ_{el} ≅ ƒ_{Δv=0} ⪅ 2·0 x 10^{-3}$ . A crude upper limit of $ƒ_{el} ⪅ 5·0 x 10^{-3}$ for the MgO(B¹Σ⁺ - A¹π) band system and results for bands of the F _2- molecule are also obtained.

References (17)

D.J. Carlson
Emittance of Condensed Oxides in Solid Propellant Combustion Products
R.W. Patch et al.
JQSRT
(1962)
P. Swings
Les bandes moléculaires dans spectres stellaires
P.C. Keenan
Classification of Stellar Spectra
P.C. Keenan
Publ. Astron. Soc. Pacific
(1957)
H. Spinrad et al.
Astrophys. J.
(1965)
A. Schadee
Bull. Astron. Inst. Netherlands
(1964)
R.W. Nicholls et al.
Allowed Transitions

There are more references available in the full text version of this article.

Cited by (12)

A novel two-stage aeration strategy for Bacillus thuringiensis biopesticide production from biowaste digestate through solid-state fermentation
2020, Biochemical Engineering Journal
Citation Excerpt :
The transition from linear to circular economy, where the value of resources, materials, and products are maintained through all the value-chain, is a necessary step to establish a more sustainable, zero waste and competitive economy. In this sense, the European Commission is elaborating action plans to change and develop new product designs, production processes, consumption habits, and waste management models to minimize environmental impact and extend the resource's lifecycle [1]. More recently, actions such as turning waste into resources and closing loops of recovered materials have been highlighted as essential building blocks of circular economy [2].
A novel aeration strategy has been developed at lab and bench-scale for Bacillus thuringiensis (Bt) derived biopesticides production through solid-state fermentation, using a mixture of digestate and biowaste as substrates. A Box-Behnken design was performed to select key parameters of the spore production process, being temperature and biodegradability the factors with a significant effect. Further tests confirmed the importance of oxygen content for spore production. Thus, a two-stage aeration strategy consisting of a microaeration phase followed by a high-rate aeration period was developed and tested. The production strategy was validated in a 22-L reactor using two different strains (Bt kusrtaki, Btk, and israelensis, Bti), demonstrating the robustness of the protocol. Maximum production of 1.3 × 10⁸ spores g^-1 dry matter for Btk and 4 × 10⁸ spores g^-1 dry matter for Bti were obtained, representing a final yield of 5 and 29 spores produced per initial CFU, respectively.
Transition probabilities in the B1∑+-X1∑+ and the B1∑+-A1∏ electronic systems of MgO
2002, Journal of Molecular Spectroscopy
Transition probabilities for the B¹Σ⁺–X¹Σ⁺ and the B¹Σ⁺–A¹Π electronic systems are presented for v=0–4 and J=0–150 in each electronic state. The functional form of the electronic transition moment for the B–X transition is taken from published ab initio results. The B–A moment is assumed to have the same form and is scaled using empirical branching ratio data. The R_e(r) are used with Rydberg–Klein–Rees (RKR) wavefunctions to calculate transition probabilities for v=0–4 and J=0–150. The RKR potentials were calculated based on empirical spectroscopic constants.
Radiative lifetimes and transition moments in MgO
1983, Journal of Quantitative Spectroscopy and Radiative Transfer
An experimental and theoretical study of several transitions in the MgO molecule is reported. The radiative lifetime of the MgO B¹Σ⁺v'=0 level is measured to be 32.7±1.7 nsec, while that of the electronic state(s) excited by 372 nm radiation (d³Δ and/or f³Π) is 11.8±0.5 nsec. The B-X and A-X transition moments are calculated using state averaged multiconfiguration self-consistent field and configuration interaction methods. With an estimate of the B-A transition moment derived from an earlier calculation, the radiative lifetime of the B¹Σ⁺v'=0 level is computed to be 24 nsec. A value of 0.23 msec is calculated for the lifetime of A¹Πv'=0.
Perturbation calculation of transition moments. Application to H<inf>2</inf> and MgO
1974, Chemical Physics
The CIPSI (Configuration Interaction by Perturbation of a multiconfiguration wavefunction Selected lteratively) method is extended to the calculation of electronic transition moments. At each step the wavefunction ψ⁰_M and ψ⁰_N for the states M and N are perturbed to the first order by the remaining Cl leading to first order corrections ψ¹_M and ψ¹_N. The zero and first order transition moments
are calculated. Selecting the most important determinants of ψ¹_M and ψ¹_N one is able to build improved zero order wavefunctions for these two states and the process is iterated. The method has been tested on several transitions of H₂ and on the X¹Σ⁺-B¹Σ⁺ transition of MgO, showing the importance of the first order correction. The stability of the results when the quality of the wavefunction is improved is satisfactory.
The results for several transitions of MgO are given; the result for the X¹Σ⁺-B¹Σ⁺ transition is very different from an experimental estimate
Experimental determination of the oscillator strengths for the A2Σ-X2Σ band system of aluminum oxide
1970, Combustion and Flame
Absolute intensity measurements have been made of the A²Σ-X²Σ band system of aluminum oxide. The measurements were performed in a cyanogen-oxygen flame system to which were added measured amounts of aluminum in the form of gaseous trimethylaluminum. From the measured atomic aluminum concentration in the flame and the measured total aluminum content, the aluminum oxide concentration was deduced on the assumption that atomic aluminum and aluminum oxide were the major aluminum species present in the flame. The electronic oscillator strength of the system was found to be f_electronle = (3.7 ± 3) × 10⁻³.
On the oscillator strengths of MgO and F<inf>2</inf>
1969, Journal of Quantitative Spectroscopy and Radiative Transfer
In a recent paper (R. P. Main, D. J. Carlson and R. A. DuPuis, JQSRT 7, 805 (1967)), measurements of oscillator strengths of electronic transitions in the MgO-, MgH-, and F₂-molecules were reported. We point out that the results reported in that paper for F₂ are almost certainly invalid, and that an error in the oscillator strengths for the MgO transitions, estimated in that paper and due to the possible existence of low-lying electronic states of MgO, was incorrectly calculated.

View all citing articles on Scopus

^∗: Mr. Main is grateful to the Aeronutronic Applied Research Laboratories, in whose employ part of this work was performed.

View full text

Article preview

Journal of Quantitative Spectroscopy and Radiative Transfer

Abstract

References (17)

Emittance of Condensed Oxides in Solid Propellant Combustion Products

JQSRT

Les bandes moléculaires dans spectres stellaires

Classification of Stellar Spectra

Publ. Astron. Soc. Pacific

Astrophys. J.

Bull. Astron. Inst. Netherlands

Allowed Transitions

Cited by (12)

A novel two-stage aeration strategy for Bacillus thuringiensis biopesticide production from biowaste digestate through solid-state fermentation

Transition probabilities in the B<sup>1</sup>∑<sup>+</sup>-X<sup>1</sup>∑<sup>+</sup> and the B<sup>1</sup>∑<sup>+</sup>-A<sup>1</sup>∏ electronic systems of MgO

Radiative lifetimes and transition moments in MgO

Perturbation calculation of transition moments. Application to H<inf>2</inf> and MgO

Experimental determination of the oscillator strengths for the A<sup>2</sup>Σ-X<sup>2</sup>Σ band system of aluminum oxide

On the oscillator strengths of MgO and F<inf>2</inf>

NoteMeasurement of oscillator strengths of the MgO(B1Σ+ - X1Σ+) and MgH(A2π - X2Σ+) band systems

Abstract

JQSRT

Les bandes moléculaires dans spectres stellaires

Classification of Stellar Spectra

Publ. Astron. Soc. Pacific

Astrophys. J.

Bull. Astron. Inst. Netherlands

Allowed Transitions

Note
Measurement of oscillator strengths of the MgO(B¹Σ⁺ - X¹Σ⁺) and MgH(A²π - X²Σ⁺) band systems