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

Main, Roger P.; Carlson, Donald J.; DuPuis, Richard A.

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

Cited by 23 publications

(3 citation statements)

References 9 publications

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“…The band oscillator strength has recently been determined in the laboratory by MAIN et al (1967). Their value is a factor of 4 smaller than Schadee's, derived from solar equivalent widths of MgH lines.…”

Section: Discussionmentioning

confidence: 99%

A study of weak molecular and atomic lines in the photospheric spectrum

Mallia¹

1968

Sol Phys

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An attempt is made to detect the lines of Mg2aH and MgZaH in the photospheric spectrum, using calculated isotope shifts. From comparisons with the Mg24H lines of the zX-ZH transition in the (0, 0) band the ratios MgZS/Mg24 --0.12 • 0.04 and Mg26/Mg 24 = 0.12 4-0.02 are derived. These are essentially the same as the terrestrial ratios. The profile of one line of MgI confirms these values.The wavelengths of MgH and C2 lines, when corrected for the gravitational red shift, indicate that macroturbulent (or streaming) velocities die out near log TO =-1.0. Frem the equivalent widths of the MgH lines a rotational temperature of 5132 • K is obtained and compared to predictions from various model atmospheres. The band oscillator strength is found to be 0.024 • 0.002, in serious disagreement with the single laboratory determination.The profiles of MgH, C2, CN and some weak atomic lines are used to derive the variation of the radial component of microturbulence with optical depth, on the assumption of streaming velocities of 2.5-3.0 km/sec. A slow increase with increasing height in the photosphere is found, over the range --1.5 < logz0< 0.2.The center-limb variation of the equivalent widths of MgH and Ca lines for a wholly inhomogeneous model is found to be the same as for a model which is homogeneous above log T0 ----1.0. With such a model as the latter, the center-limb variation of the profiles of the selected molecular and atomic lines is moderately-well reproduced by an anisotropic microturbulent velocity with a tangential component of 3 km/sec which seems to be constant with height over the range considered.

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Section: Discussionmentioning

confidence: 99%

A study of weak molecular and atomic lines in the photospheric spectrum

Mallia¹

1968

Sol Phys

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“…Huron et al (1974) performed configuration interaction calculations of ten transition dipole moments in the singlet and in the triplet manifolds. They were led to criticize a previous experimental determination of the B 1 £ + -X 1 U + oscillator strength by Main et al (1967;1969). The discrepancy between experiment and theory for this system and others was kept going by the shock-tube quantitative absorption data of Evans & Mackie (1977) and of Svyatkin et al (1980a) that both involved however perilous number density determinations.…”

Section: Alkaline-earth Monoxides: Beo Mgo Cao Sro Baomentioning

confidence: 99%

Oscillator Strengths and Excited State Lifetimes in Metallic Hydrides and Oxides

Schamps

1994

International Astronomical Union Colloquium

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It is really impressive to see the amount of information astrophysicists have been able to extract from the analysis of that faint glimmering light that stars se,nd to tell us about them. The main piece of this analysis consists in dispersing the light to get the spectrum, that is to say intensity versus wavenumbers. From the measurements of wavenumbers it is possible to identify the atomic and molecular species from comparison with high-resolution laboratory spectroscopic data. Once the constituents have been identified, models can be constructed in order to simulate the metabolism of circumstellar atmospheres. In such models a crucial point is the abundance of the identified atomic and molecular constituents.

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“…Recently Saxon et al [44] have reported electronic transition moments for the B''X'-X2X', A2n-J?C+ and B'2C'-AZII band systems of MgH. They used a basis set consisting of 66 Slater-Type-Orbitals and both single, double and triple valence excitations with respect to multi-configuration SCF reference states were included in the CI calculations, Radiative lifetimes have not been measured for MgH and only substantially deviating results (0.002 [45] and 0.257 [46]) for the band absorption oscillator strength, foe, of the A-X transition are available. Saxon et al [44] did not calculate radiative lifetime from their transition moments either, but they determined foo(A-X) t o be 0.161.…”

Section: Mghmentioning

confidence: 99%