Band oscillator strengths of the intersystem transitions of CO

Abstract

Articles you may be interested inElectronic transition dipole moments and dipole oscillator strengths within Fock-space multi-reference coupled cluster framework: An efficient and novel approach J. Chem. Phys. 138, 094108 (2013); 10.1063/1.4793277Rotational effects in the band oscillator strengths and predissociation linewidths for the lowest Π u 1 -X Σ g + 1 transitions of N 2 Temperature-dependent absorption strengths for transitions from the ground state to the mutually perturbed A 1 Π(v=1) and d 3 Δ 1 (v=5) states of CO Absorption oscillator strengths of 18 intersystem bands of CO between 1360 and 1620 Å originating from the ground state and involving the aЈ 3 ⌺ ϩ , e 3 ⌺ Ϫ , and d 3 ⌬ states have been measured using synchrotron radiation as a background source. They have also been calculated using the published molecular parameters provided by the standard spectroscopic perturbation analysis, including the spin-orbit interaction with the nearby A 1 ⌸ state. It was found, however, that the model used in that analysis had to be extended in order to take into account the contributions of several vibrational levels of the A state to the intensity of a given singlet-triplet band. The present measurements are in good agreement with the predictions of this extended model. The puzzling discrepancies reported earlier between oscillator strength or rotationally resolved lifetime measurements and standard calculations are now well understood as well as the temperature variation of some of these band-integrated oscillator strengths. Line and band oscillator strengths of the intercombination transitions can now be reliably predicted at all temperatures and used for the measurement of large CO column densities, especially in interstellar molecular clouds, when the allowed bands normally used are saturated.

Oscillator Strengths for B – X , C – X , and E – X Transitions in Carbon Monoxide

“…In particular, the results of Chan, A Cooper, & Brion (1993), Smith et al (1994), Federman et al (1997), Jolly et al (1997), Zhong et al (1997), Stark et al (1998), and Eidelsberg et al (1999) for AÈX (v@ \ 5È16) agree within experimental uncertainties, typically 10%. As for the triplet-singlet bands, the analysis of Rostas et al (2000) conÐrms the f-values inferred from HST observations by Federman et al (1994). The accuracy of these f-values now is also 10%.…”

Oscillator strengths for transitions to Rydberg levels in $\mathsf{^{12}}$C$\mathsf{^{16}}$O, $\mathsf{^{13}}$C$\mathsf{^{16}}$O and $\mathsf{^{13}}$C$\mathsf{^{18}}$O between 967 and 972 Å

“…The procedure just described was executed using two independent codes previously applied to derive CO oscillator strengths, one by Federman et al (1997) for A−X transitions and for the B−X, C−X, and E−X Rydberg transitions, the other by Eidelsberg et al (1999) for A−X bands and by Rostas et al (2000) for intersystem transitions. The agreement in results from the two codes was excellent, typically within 2%.…”

“…Only the line intensities are well defined. Indeed, as shown in Rostas et al (2000), the band oscillator strengths even become temperature dependent because the mixing coefficients vary with J and the contribution of different J levels to a given band changes with temperature.…”

“…In the same wavelength range, the triplet-singlet intersystem bands are typically 2 to 6 orders of magnitude weaker and can be used for dense clouds where the A−X bands are optically thick. The large discrepancies that initially appeared between observed and predicted oscillator strengths for these transitions (Federman et al 1994;Sheffer et al 2002) have been resolved thanks to a new theoretical model that allows a reliable calculation of band and line oscillator strengths (Rostas et al 2000;Eidelsberg & Rostas 2003).…”

The interaction in CO+: Deperturbation analyses of B–A and A–X bands of 12C16O+, 13C16O+ and 14C16O+

“…Determination of physically meaningful molecular constants for the A state often requires consideration of interactions with two distant X(t*) levels. This situation is reminiscent of that described by Rostas et al [43] in a study of CO absorption oscillator strengths from the ground state to the excited a 0 3 R þ ; e 3 R À and d 3 D states. Reliable theoretical calculations of these intersystem oscillator strengths could only be achieved by taking account of interactions with several A 1 P t-levels, and not just the nearest neighbor.…”