Rr QrTsQrT490 Temperature-dependence of the bandwidth parameter The bandwidth parameter, Aa, scales as the separation, \J8BkTj he, between the P and R maxima in the band envelope, and so Temperature dependence of the line half-width The Doppler line half-width, bD, and the collisionally induced line half-width, bc, scale with temperature according to where the parameter n for molecular bands takes a mean value close to 0.7, to a good approximation. From the elementary kinetic theory of gases n = 1/2 for a collisionally broadened rotational line. This arises from the fact that bc for a line scales as the frequency of collisions (see §7.3.2) which is proportional to n\/T, where n is the number density given by n = p/kT. Both theoretical work and experimental work indicate that for rotational lines of molecular bands, the parameter n is about 3/4 near the band centre decreasing to 1/2 for lines in the band wings, for atmospheric temperatures (see also the HITRAN database discussed in §4.7 for individual line values for each molecule).

Was this article helpful?

0 0
Guide to Alternative Fuels

Guide to Alternative Fuels

Your Alternative Fuel Solution for Saving Money, Reducing Oil Dependency, and Helping the Planet. Ethanol is an alternative to gasoline. The use of ethanol has been demonstrated to reduce greenhouse emissions slightly as compared to gasoline. Through this ebook, you are going to learn what you will need to know why choosing an alternative fuel may benefit you and your future.

Get My Free Ebook

Post a comment