Nitrogen vibrational relaxation time

Young, JChemPhys 27(5), 1149-55(1957) (Measurement of vibrational relaxation time in nitrogen by means of an acoustical resonance cavity) 4) Dunkle s Syllabus (1957-1958), pp 57-8 389 5) M. Saikoff... 

At To = 10 2 to 10 3 s, we have t / = lO to 10" s. The magnitude essentially exceeds the relaxation times of vibration-excited nitrogen on glass (10" s [107]), a fact that points to the complicated nature of 02( ) deactivation on pure glass surface. As the de-excitation of... 

Electrons can be ejected by ultra-violet light from aromatic molecules in solution (for a review, see Lesclaux and Joussot-Dubien, 1973). Recently Klaning et al. (1973) have reported that solvated electrons are formed from 2-naphthol by a 337-1 nm pulse from a nitrogen laser, and deduce that the rate of electron formation is higher than the rate of vibrational relaxation to the lowest excited singlet state. Since the electrons are relatively long-lived and take no further part in the ns time-scale reactions, the only effect they have upon the acid-base investigation is to necessitate a correction to the absorption spectra of the transient species under observation. 

It should be noted that there is a considerable difference between rotational structure narrowing caused by pressure and that caused by motional averaging of an adiabatically broadened spectrum [158, 159]. In the limiting case of fast motion, both of them are described by perturbation theory, thus, both widths in Eq. (3.16) and Eq (3.17) are expressed as a product of the frequency dispersion and the correlation time. However, the dispersion of the rotational structure (3.7) defined by intramolecular interaction is independent of the medium density, while the dispersion of the vibrational frequency shift (5 12) in (3.21) is linear in gas density. In principle, correlation times of the frequency modulation are also different. In the first case, it is the free rotation time te that is reduced as the medium density increases, and in the second case, it is the time of collision tc p/ v) that remains unchanged. As the density increases, the rotational contribution to the width decreases due to the reduction of t , while the vibrational contribution increases due to the dispersion growth. In nitrogen, they are of comparable magnitude after the initial (static) spectrum has become ten times narrower. At 77 K the rotational relaxation contribution is no less than 20% of the observed Q-branch width. If the rest of the contribution is entirely determined by... 

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