RKR Franck-Condon Factors Research Articles

Intensity and wavelength measurements for the CS + (A 2II−X 2∑ +) and CS(A 1II−X 1∑ +) band systems excited by the reaction of metastable He(2 3S) with CS 2

The interaction of He(2 3 S) with CS 2 produces relatively strong emission from the CS + (A 2 II−X 2 ∑ + ) and CS(A 1 II−X 1 ∑ + ) systems; weaker emission is observed from CS 2 + (A 2 II u −X 2 II g ), CS 2 + (B 2 ∑ u + −X 2 II g ), CS(a 3 II−X 1 ∑ + ), some unassigned transitions, and atomic emission (mainly from S * ) in the vacuum ultraviolet. Several new CS + (A−X) emission bands were observed and these yield improved spectroscopic constants for both the CS + (X) and CS + (A) states. Available data for Δ H fo Q (CS) are critically assessed, and estimates of Δ H fo Q (CS + )=326.4±0.7 and D 0 0 (CS + )=147.8±0.9 kcal mole −1 are obtained. The experimentally observed band intensities were combined with Franck-Condon factors calculated from a Morse potential for CS + (X) and an RKR potential for CS + (A) to obtain vibrational populations, and to compare calculated and experimental radiative branching ratios. The band intensities from the CS(A 1 II, v ′=0–4) levels were combined with calculated RKR Franck-Condon factors to analyze the dependence of the electronic transition moment on r-centroid. The other emission systems observed from the He(2 3 S)+CS 2 reaction also are summarized, and some aspects of the quenching mechanism are discussed and compared to the photoionization of CS 2 .

RKR Franck—Condon factors and absorption cross-sections for rotational transitions in the A 2Π i—X 2Π i system of ClO

Available spectroscopic data are used to obtain RKR potential energy curves for the A 2Π i and X 2Π i states of ClO. Franck—Condon factors for the A–X system are reported. With the recent revision in the A state vibrational numbering, the results are more reliable than those of previous work with Morse potentials. The known line-widths and calculated line strengths for the A–X bands are used in computer generation of absorption cross-section profiles for individual bands. The cross-sections are obtained on an absolute basis by computer simulation of band head extinction coefficient measurements. A simple procedure is described for the calculation of photolysis rates in the banded region of ClO (A ← X).

RKR Franck-Condon factors for blue and ultraviolet transitions of some molecules of astrophysical interest and some comments on the interstellar abundance of CH, CH + and SiH +

RKR Franck-Condon factors for thirteen of the blue and ultraviolet transitions of AlF, AlO, BH, BD, CH, CD, CH +, SiO and SiH + have been calculated. The interstellar abundances of CH, CH + and SiH + are discussed with regard to recent laboratory measurements, our Franck-Condon factors, and observations of the sun and the interstellar medium.

Radiative lifetimes and absolute oscillator strengths for the SiO A1Π- X1Σ + transition

Measurement of a radiative lifetime of 9.6 ± 1.0 nsec for the SiO A 1Π-state is reported. RKR Franck-Condon factors have been computed and, with these, absolute oscillator strengths are calculated. A band system at ∼ 3022Å has been found that may be due to SiO +, but the band is not resolved at our experimental resolution, and identification remains uncertain. The upper state of the carrier of this spectrum has a radiative lifetime of 8.3 ± 0.8 nsec.

The electronic transition moment of the N +2 first negative system

The intensity ratio of the (1, 3) and (1, 2) bands of the N + 2 first negative system was found to be smaller than in a previous experiment. This permits a closer fit of R 2 e as a function of the r-centroid. Using existing lifetime data and RKR Franck-Condon factors the new fit is given by R 2 e = 0.36(a oe) 2 (r - 0.72).

RKR Franck-Condon factors for blue and ultraviolet transitions of some metal oxides

RKR Franck-Condon factors and r-centroids are presented for eleven blue and ultraviolet systems in the oxides of B, Be, Ca, Sr, and Zr.

Absolute Oscillator Strengths for the CH+, CD+, and BH A 1Π–X 1Σ+ Transition

Radiative lifetime measurements for the CH+(CD+) A 1Π state (70 ± 25 nsec) and for the BH A 1Π state (159 ± 16 nsec) are reported. Absolute oscillator strengths are computed using RKR Franck–Condon factors. Astrophysical implications of these data are indicated.

Frank-Condon factors and absolute oscillator strengths for NH, SiH, S 2 and SO

RKR Franck-Condon factors and r-centroids have been calculated for transitions of NH, SiH(SiD), S 2, and SO. Radiative lifetime data from this laboratory are used to derive absolute transition probabilities for the prominent transitions. The derived absolute transition probabilities are compared with literature values.