Mass-spectrometry of cluster molecular beams

Abstract

An apparatus with gas-dyhamical molecular beam source (GMBS) has been developed providing formation of cool supersonic atomic and molecular beams with 10 18 part/cm 2 s intensity and angular divergence of < 1.5°. The apparatus design enables one to generate cluster beams of various substances. All parameters of the apparatus are continuously controlled in an automated mode. An oil-free vacuum pumping provides a limiting pressure from 2 × 10 −7 up to < 10 −9 Torr allowing one to study the interaction of gas flows with solid surfaces with subsequent structural analysis by means of a photoelectron X-ray spectroscopy. The cluster beams of the Ar atoms, CO 2 molecules and Ar(CO 2) mixture have been studied by means of a mass-spectrometric method. The production of the Ar N X-like and (CO 2) N X-like associated clusters (where X = H, H 2 and OH) has been observed. In the mass-spectrum for the argon + carbon dioxide mixture, besides the basic (parent) Ar N and (CO 2) N clusters, the composite [Ar n (CO 2) m ] N -like clusters have been found comprising the mass peaks related to the various combinations of daughter Ar n and (CO 2) m clusters with ( n + m = N) total size of incorporated molecules.