The a4Σ−–X2Π Electronic Transition of SiF

1973 ◽  
Vol 51 (6) ◽  
pp. 634-643 ◽  
Author(s):  
R. W. Martin ◽  
A. J. Merer
Keyword(s):  
Electronic Transition ◽  
Energy Levels ◽  
High Dispersion ◽  
Rotational Line ◽  
Molecular Constants ◽  
Transition Moments

The a4Σ−–X2Π transition of SiF at 3360 Å has been reinvestigated at high dispersion. Our new rotational line assignments show that the energy levels of the 4Σ state, which is very close to case (b) coupling, can be fitted with one rho-type doubling parameter (γ) rather than the two proposed by Hougen to account for Verma's previous results. The relative intensities of the branches have been interpreted in terms of two transition moments, whose ratio shows that the intensity of the a–X system comes mainly from the so far uncharacterized σπ22Σ+–X2Π transition. 'Equilibrium' molecular constants for the a4Σ− state have been derived from analysis of the overlapping sequence bands.

Directions of the Electronic Transition Moments in Dioxido-p-terphenyl

1988 ◽  
Vol 43 (3) ◽  
pp. 193-195 ◽  
Author(s):  
Z. Gryczyński ◽  
A. Kawski
Keyword(s):  
Electronic Transition ◽  
Absorption And Emission ◽  
Dichroic Ratio ◽  
Transition Moments ◽  
Fluorescence And Phosphorescence

The directions of the absorption, fluorescence and phosphorescence transition moments of dioxido-p-terphenyl are determined from measurements of the absorption and emission anisotropies as functions of the dichroic ratio in stretched PVA films.

scholarly journals Effects of Stellar Rotation on Spectral Classification

1979 ◽  
Vol 47 ◽  
pp. 87-94
Author(s):  
Arne Slettebak ◽  
Thomas J. Kuzma
Keyword(s):  
Systematic Errors ◽  
Stellar Atmospheres ◽  
High Dispersion ◽  
Rotational Line ◽  
Spectral Classification ◽  
Line Broadening ◽  
Stellar Rotation ◽  
First Case ◽  
Balmer Lines ◽  
Physical Changes

AbstractStellar rotation may affect the strengths of lines used in spectral classification because of effects of plate resolution and also because of physical changes in the rotating stellar atmospheres. In the first case, the importance of using standard stars with appropriate rotational line broadening in classifying spectra of relatively high dispersion (resolution) is emphasized. Rotational effects on weak lines in general and on the Balmer lines may cause systematic errors in the assignment of spectral types and luminosity classes unless the standard stars are chosen with line broadening similar to that of the star to be classified. With regard to physical changes in the rotating atmospheres, we have extended the earlier work of Collins to include the Balmer lines plus additional lines of He I and Si II which are important in spectral classification over a wider range of spectral types.

Electronic Transition Moments of 2-Aminopurine

1997 ◽  
Vol 119 (13) ◽  
pp. 3114-3121 ◽  
Author(s):  
Anders Holmén ◽  
Bengt Nordén ◽  
Bo Albinsson
Keyword(s):  
Electronic Transition ◽  
Transition Moments

Rotational line strengths in 3Δ–3Σ electronic transitions. The Herzberg III system of molecular oxygen

1986 ◽  
Vol 64 (1) ◽  
pp. 36-44 ◽  
Author(s):  
C. M. L. Kerr ◽  
J. K. G. Watson
Keyword(s):  
Molecular Oxygen ◽  
Satisfactory Agreement ◽  
Electronic Transitions ◽  
Rotational Line ◽  
Spin Orbit ◽  
First Order ◽  
Order Relations ◽  
Transition Moments ◽  
Wave Numbers ◽  
Line Strengths

Electronic transitions of the type 3Δ–3Σ are forbidden in the absence of spin–orbit or orbit–rotation coupling, but spin–orbit perturbations produce three transition moments, two perpendicular (Y1 and Y2) and one parallel (Z1) while low-order orbit–rotation couplings introduce three further perpendicular transition moments (X1, X2, and X3). Formulas are presented for the rotational line strengths in a 3Δ(a)–3Σ(int) transition in terms of these parameters and are applied to recent data of Coquart and Ramsay for the Herzberg III system [Formula: see text] of molecular oxygen. It is shown that all six parameters are significant, and that there are noticeable departures from the first-order relations Y1 = Y2, Z1 = 0, X1 = X2 = X3. The observation of orbit–rotation intensity effects led to the first identification of lines of the Ω′ = 3 subbands of the 4–0 to 7–0 bands of the Herzberg III system, which are forbidden for the spin–orbit mechanism. The wave numbers of these lines are in satisfactory agreement with the analysis of the A′3Δu → a1Δg emission by Slanger and Huestis.

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