Visible chemiluminescence from the high-pressure reactions of F atoms with CH3I and CH2I2

Abstract

Visible chemiluminescence in the region 400–890 nm was measured from the high-pressure (ca. 0.4 mbar) reactions of F atoms with CH₃I and CH₂I₂. Emission was observed from electronically excited IF*(B), HCF*(Ã) and CH^*(A) and from vibrationally excited HF^‡(X). There are essentially no differences in the observed chemiluminescence spectra from the two reactions and no major dependence on the source of F atoms (discharge of F₂+ He or CF₄). A possible mechanism for the formation of IF* involves the intermediate species CH₃IF or CH₂I₂F. It is suggested that HCF*, CH* and HF‡ may be formed by the reactions of F or F₂ with CH or CH₂ and such a mechanism may be applicable to all high-pressure fluorine reactions with substituted methanes. Some studies of chemiluminescence in other high-pressure systems (F + CH₃Br, CH₃OH, ICl and HI) are also reported.