Laser line strengths

In the upper parts of Figs. 6a-c the time-dependent Rabi frequencies of both laser pulses are shown for different delays. In all cases the dump laser pulse has a higher Rabi frequency than the pump laser pulse and twice its duration. Note that the Rabi frequency is proportional to the laser held strength and therefore to the square root of the pulse intensity. In the lower part the population dynamics for the three different pulse sequences is shown. The part of population transferred to the ionization continuum is indicated by a strong line. 

The selection of a laser and an absorption feature represents a compromise between the absorption line strength the characteristics of the laser emission at the wavelength of the line and absence of interferences at this wavelength from other atmospheric gases. 

Line-strengths for four transitions of OH near 2.93 /xm 808 from diode laser study... 

The wave functions used in the expressions for the line strengths are precisely those deduced by an analysis of the free-ion energy level structure. Therefore, only three new parameters, the s, have been introduced to account for the line strengths. This scheme has been remarkably successful in modeling experimental observations in both crystal and solution environments. It also accommodates the existence of the "hypersensitive" transitions. Peacock (30) has recently reviewed the field with regard to lanthanide f-f transitions. The simplicity of this scheme has been utilized by Krupke (31) and Caird (32) to predict potential laser transitions in the lanthanides. 

Carbon monoxide metastable TOF spectra for ketene photodissociation at 351 nm were taken from jco = 3-18. There was no difference in the shapes of the TOF spectra when the polarization of the probe laser was changed with respect to the flight path. Thus, our results are not sensitive to whatever vector correlations may exist in this photodissociation and the line strength factor of Eq. 38 can be ignored. The resulting F( lrans) functions reveal that... 

Thus far, the > (03) of oxy-Hb has not been observed by RR spectroscopy either because the Fe-02 CT band cannot be reached by available laser lines or because its oscillator strength is too small for resonance excitation. Using IR difference techniques, Caughey et al. observed two bands at 1155 and 1107 cm" which are shifted to 1096 and 1064 cm", respectively, by 02-" 02 substitution. These workers attributed the splitting of the (02) to Fermi resonance between the unperturbed 1 (02) 1135 cm" ) and the first overtone... 

Here, excitation spectroscopy shows its strength. One irradiates the sample with an extremely sharp laser line (down to 0.001 cm ). Detection is accompUshed via the integrated fluorescence, which can readily be separated from the excitation light using filters, as the absorption and the fluorescence do not overlap. The emission hes at a higher quantum energy. With this method, it is even possible to identify and distinguish the isotope C, present with its natural abundance of only 1.1%, at different positions within the molecules [21]. 

II. T.J. Johnson, F.G. Wienhold, J.P. Burrows, G.W. Harris, H. Burkhard Measurements of line strengths in the HO2 d1 overtone band at 1.5 mm using an InGaAs laser,... 

To make quantitative statements about the product internal distribution a computer program is utilized to simulate the observed excitation spectrum [10]. As input for the calculations we estimate the relative vibrational and rotational populations. Each line is weighted by the population of the initial (v, J ) level, by the Franck-Condon factor and the rotational line strength of the pump transition. At each frequency, the program convolutes the lines with the laser bandwidth and power to produce a simulated spectrum such spectra are compared visually with the observed spectra and new estimates are made for the (v ,J") populations. Iteration of this process leads to the "best fit" as shown in the lower part of Fig. 3. For this calculated spectrum all vibrational states v" = 0...35 are equally populated as is shown in the insertion. The rotation, on the other hand, is described by a Boltzmann distribution with a "temperature" of 1200 K. With such low rotational energy no band heads are formed for v" < 5 in the Av = 0 sequence and for nearly all v" in the Av = +1 sequence (near 5550 A). 

Varghese PL and Hanson RK (1980) Tunable infrared diode laser measurements of line strengths and collision widths of 2C 0 at room temperature. Journal of Quantitative Spectroscopy Radiative Transfer 24 279. 

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