Pulsed matrix isolation. A comparative study

Abstract

Preparation from the gas phase of matrix-isolated samples at low temperature can be achieved by very slow deposition (SSO, slow spray-on) or by deposition in pulses (PMI, pulsed matrix isolation, first introduced by Rochkind). Infra-red experiments which compare SSO and PMI are described for a variety of systems. These show that (a)“fractional distillation” is similar for both methods, (b) PMI generally produces significantly less polymer than SSO, (c) Beer's law is obeyed for PMI even after many pulses, (d) the spray-on geometry for PMI is not critical and (e) contamination due to apparatus leaks is significantly lower for PMI than SSO. These results combined with the great time economy of PMI and the generally clearer matrices obtained suggest that PMI should be used in preference to SSO where practicable.