Experimental determination of transition probabilities and radiative lifetimes

Abstract

Reliable values for transition probabilities are widely required, particularly in astrophysics and laboratory plasma physics. Most such values are obtained experimentally; calculations tend to be of doubtful reliability unless they have been experimentally vindicated. The experimental methods described in this chapter are, however, of rather wider application than the title indicates, because the same methods can be used to determine parameters of plasmas. For instance, measurements of emission intensities and absorption coefficients yield the product of a population density and an oscillator strength, and if the latter is known the former can be deduced. This aspect is followed up in Chapter 13. The terms ‘transition probability’ and ‘oscillator strength’ are used interchangeably, since either can be found from the other by the relations summarized in Tables 11.1–11.4.