Phosphorus in the burnt gas from fuel-rich hydrogenoxygen flames

Green bands, attributed to HPO by Lam Thanh My and Peyron, are emitted from the burnt gas of fuel-rich flames containing a trace of trimethyl phosphate, but not from lean flames. Their intensity is proportional to [phosphorus]0·1±0·1 [H]2[H2O]0·5±0·5[H2]0·1±0·5exp{− (5±5) κcal/RT} where [phosphorus] represents the addition of trimethyl phosphate. The dependence on [H]2 is good to the nearest integral power. The uncertainty by the factor {[H2O][H2]}0·5 reflects the small change in this quantity in most of the experiments. An interpretation is offered which is consistent with the identification of the emitter as HPO: that the flame intensity is proportional to [H] [PO], and that the phosphorus is present mostly as P2 molecules which are equilibrated according to: P+O-=P+POP+OH=PO+H The flame result can also be interpreted by an intensity proportional to [H] [P] with the same equilibria among P2, PO and P. On either interpretation, the phosphorus must be considered to be mainly present as P2 molecules.