Optically pumped lasers from Na2 D 1Πu state

A study of the B1Πu→ X1Σ+gsystem of Na2

“…In a second step, in order to determine frequencies for transitions that cover both X 1 + g (up to v = 62) and B 1 u (up to v = 33) states up to dissociation, our results were combined with previous data from the literature. In this sense, we have incorporated into the current analysis the energy terms between v = 46 and 62 reported by Barrow et al [23] and Babaky and Hussein [24] for the X 1 + g state, and between v = 30 and 33 for the B 1 u excited state reported by Vedder et al [29] and Richter et al [31]. Small typographical mistakes in T 46,15 = 5514.3496 cm −1 and T 52,15 = 5824.7242 cm −1 were corrected from table I of [23].…”

“…Small typographical mistakes in T 46,15 = 5514.3496 cm −1 and T 52,15 = 5824.7242 cm −1 were corrected from table I of [23]. Also in [23,24] the Y 20 , Y 11 and Y 00 Dunham coefficients should be negative in sign. With regard to the information included in the fits, lines with differences in wavenumber greater than 0.20 cm −1 with respect to the calculated values obtained from Dunham coefficients reported by Kusch and Hessel [27] (for fluorescence series within their analysis range) were not considered in the current analysis.…”

“…Potential energy curves of the X 1 + g and B 1 u electronic states are known accurately up to dissociation. The potential energy curve for the X 1 + g state of the sodium dimer obtained from experimental information are given by Kusch and Hessel [27], Zemke and Stwalley [30], Babaky and Hussein [24], Abeelen and Verhaar [59], Chung et al [60] and also reported by our laboratory [48]. For the X 1 + g ground electronic state the innermost RKR turning points for the last vibrational levels v = 60, 61 and 62 calculated are out of line with the rest of the adjoining inner RKR turning points with a positive slope whose magnitude increases monotonically with increasing energy.…”

“…For the proper assignment of the intermediate levels in such two step excitations, precise excitation transitions and molecular constants of the corresponding electronic states are necessary, which motivates further spectroscopic studies of electronic states implied in the pump laser transition. Moreover, because of its simple molecular structure, ease of production, stability at a precise pressure and temperature for a long time, and favourable absorption and emission cross sections, investigation of optically pumped laser (OPL) sodium dimers is of special interest (see, for example, [18][19][20][21][22][23][24]). Alkali dimer lasers are not only of practical use in conventional molecular spectroscopy but furthermore allow studies of fundamental processes such as the parametric interaction of two laser fields with a molecule, the saturation of molecular transitions, and the influence of collisions on the line shape and intensity of the laser transitions.…”

“…In order to enlarge the data set of transitions within the B 1 u → X 1 + g band system, which cover both X 1 + g (involving transitions for v up to 62) and within the B 1 u (involving transitions for v up to 33) states up to dissociation, the results were combined with previous data from literature. In this sense, we have incorporated into the current analysis the energy terms between v = 46 and 62 reported by Barrow et al [23] and Babaky and Hussein [24] for the X 1 + g state, and u → X 1 + g system of Na 2 1937 between v = 30 and 33 for the B 1 u excited state reported by Vedder et al [29] and Richter et al [31]. Keeping in mind that the experimental information reported by Kusch and Hessel [27] included accurate measurements of the absorption spectrum of the B 1 u ← X 1 + g system at relatively low vibrational quantum numbers, we also included in our analysis information on term values from Kusch and Hessel [27] for the lowest rovibrational levels, since these data are outside our experimental range.…”