The Life of Atomic States and the Intensity of Spectral Lines

Abstract

It has recently been possible to explain most of the strong nebular lines as lines arising from electron jumps from metastable states in oxygen and nitrogen. - In the nebulae the emission of spectral lines can be observed under conditions of much higher rarefaction than can be found in any other terrestrial or astronomical source. Since these nebular lines occur only under these conditions, this very definitely indicates that the electron jumps causing them take place spontaneously without the interference of outside fields due to other ions, that can often be used to explain jumps of this sort when they are observed in terrestrial sources. This constitutes then the first direct evidence that metastable states are not absolutely metastable but are states of long mean life, i.e., states from which the probability of a spontaneous jump in unit time is very small.