Sequence bands

XB2u — XAg system of 1,4-difluorobenzene, with a weak overlapping sequence band labelled Bj. (Reproduced, with permission, from Cvitas, T. and Hollas, J. M., Mol. Phys., 18, 793, 1970)... 

A reduced width of the main sequence band and the avoidance of the domain of the Luminous Blue Variables (LBVs) in the HR diagram. 

The most important conclusions of these dynamical studies is that van der Waals clusters behave in a statistical manner and that IVR/VP kinetics are given by standard vibrational relaxation theories (Beswick and Jortner 1981 Jortner et al. 1988 Lin 1980 Mukamel and Jortner 1977) and unimolecular dissociation theories (Forst 1973 Gilbert and Smith 1990 Kelley and Bernstein 1986 Levine and Bernstein 1987 Pritchard 1984 Robinson and Holbrook 1972 Steinfeld et al. 1989). One can even arrive at a prediction for final chromophore product state distributions based on low energy chromophore modes. If rIVR tvp [4EA(Ar)i], a statistical distribution of cluster states is not achieved and vibrational population of the cluster does not reflect an internal equilibrium distribution of vibrational energy between vdW and chromophore states. If tvp rIVR, and internal vibrational equilibrium between the vibrational modes is established, and the relative intensities of the Ar = 0 torsional sequence bands of the bare chromophore following IVR/VP can be accurately calculated. A statisticsl sequential IVR/VP model readily explains the data set (i.e., rates, intensities, final product state distributions) for these clusters. 

For the same reason, no convective core overshooting was invoked. This has been applied in many massive star calculations in the recent years in order to obtain a wider main sequence band (cf., e.g., Schaller et al. 1992). However, as rotationally induced mixing has a very similar effect (e.g., Langer 1992, Fliegner et al. 1996), the interpretation that the main sequence widening is due to rotation and thus that the convective cores of non-rotating stars are not extended over their sizes predicted by the Schwarzschild criterion was adopted. 

The identification of the modified residue is established when the sample is co-electrophoresed with a sequence (Section 4.4.3.1.3). Since the reverse transcriptase stops or pauses 3 of the modified band, the dideoxy sequencing bands are displaced by one base relative to the modified base, i.e. if a residue is modified the corresponding band will appear as one nucleotide shorter than the base will appear in the sequence lane. 

Alternatively, when the laser frequency is tuned to the sequence band at 37321.1 cm , 37471.6 cm and 37595 cm , respectively, the 16 vibrational state acts as an intermediate state in S]. As shown in Fig. 1b for this particular transition again state-selected ions are produced, however, now almost exclusively in the 16 state with a well defined internal energy of some 40 meV, again preserving the vibrational character of the excited intermediate state into the ion. 

The intersystem crossing is practically unaffected by collisions. If initial populations of Si vibronic levels are close to the Boltzmann equilibrium (this may be done by a simultaneous pumping of the Oo band and of the neighbor sequence bands), the fluorescence lifetime of naphthalene is independent of the added gas pressure (Soep et ai, 1973). The initial triplet yield is equally pressure independent (Schroder et ai, 1978). 

Fig. 5.2. Distribution of lines in the branches of the two regular CO2 laser bands upper half) and sequence bands lower half). All the lines shown have been observed, with typical peak powers as shown. For...

Fig. 5.3. Schematic diagram of the 2q>paratus used to produce lines in the CO2 laser sequence band and to measure their frequencies. The top laser oscillates on sequence or hot band transitions because of the presence of the hot cell. In this particular case the C 02 isotope is in use. The other two lasers operate on distinct regular CO2 lines. Other experimental details are discussed in the text From [5.9]. Reproduced with the permission of the National Research Council of Canada...

Figure 5.3 shows some of these techniques in an experimental arrangement designed to produce sequence band lines and to measure their frequencies. The hot cell is clearly seen in the top laser the two reference lasers operate on the regular bands and are frequency-stabilized by means of the flourescence cell technique [5.3] which I will not discuss further. Output from all three lasers combines on a non-linear device to produce mixing products — in this experiment neither of the known frequencies f and /2 needs to be particularly close to the unknown frequency /s because of the measuring scheme chosen (f 2/2 — /i). 

Fig. 5.5. Distribution of lines in the regular upper) and sequence lower) bands of the N2O laser. Shown is the calculated relative gain, pointing downwards for the sequence band lines for the sake of clarity. From [5.5]...

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