A molecular beam scattering apparatus for surface chemiluminescence studies. Preliminary results for emission of excited K atoms.

A molecular beam scattering apparatus has been constructed for the study of surface chemiluminescence, i.e. the emission of light during a molecule-surface reaction. The apparatus consists of a beam forming stage designed for molecular and atomic chlorine, and a scattering chamber. The scattering chamber houses the sample, an alkali evaporation source, and a rotatable flange which holds the detectors; (i) the imaging optics of the photon detector, (ii) a mass spectrometer detector and (iii) a charged particle collector. The performance of the apparatus is demonstrated for a beam of chlorine molecules impinging on continuously evaporated or freshly evaporated potassium films. Intensity versus chlorine exposure and angular intensity distributions are presented for the K(4p ->4s) atomic line emission of the K+Cl$_2$ surface chemiluminescence spectrum