The opacity of the atmosphere of the sun and the negative hydrogen ion

Abstract

The negative hydrogen ion is a helium-like atom produced by the combination of an electron with a neutral hydrogen atom. Though it has been discovered experimentally (mass spectrograph) it is still impossible to produce it in large proportion in the laboratory for a direct s tudy of its physical characteristics, and the wave mechanics has so far been the only tool by which we could approach this ion. The first of the theoretical works on Hwas done by H y 11 e r a a s 1). H y 11 e r a a s proved ist stability and found for its ionization energy 0,70 e.v., a figure very close to the value to which the extrapolation of the known ionization potentials of helium-like atoms leads. The value now adopted for this ionization energy, which is also called electronic affinity of the neutral hydrogen atom is 0,75 electron volt. The low value of this potential makes it improbable that another stable quantised state of the ion exists. Thus, the absorption spect rum of Hwhich corresponds to its dissociation into a neutral hydrogen atom and a free electron must reduce to a continuum similar to the continuum associated with the head of an atomic spectral series, the wave length of its edge being given by the formula hc -0,75 electron volt. ?,