High resolution molecular photoelectron spectroscopy I. Fine structure in the spectra of hydrogen and oxygen

The processes which set fundamental limits to the minimum line widths observable in photo­electron spectroscopy are outlined. An over-all limit of about 0.002 eV is deduced as the smallest attainable line w idth in ordinary circumstances. A photoelectron spectrometer is de­scribed which uses focusing deflexion in a radial electrostatic field for energy analysis. This instrum ent has energy resolution of 0.015 eV, smaller than the normal width of rota­tional envelopes in spectra of polyatomic molecules. The applications to the study of mole­cular hydrogen and oxygen is described.