The visible emission spectra of iodine and bromine monofluorides and their dissociation energies

This is the authors' abstract. We don't add key points for this paper.

A new emission band spectrum has been observed in the iodine-fluorine flame of reaction and has been assigned to the IF molecule. A similar type of spectrum is emitted by the brominefluorine flame and is shown to be an extension of the BrF system already known in absorption. Both these systems probably arise from a 3II0+-> 1E transition. Vibrational analyses of the two spectra give the following constants: IF ve = 19054 cm.-1 w'e + 412.5 x'ew'e = 3.8 v00 = 18955 cm.-1w"e = 610 x''ew''e = 3 BrF ve = 18650 cm.-1w'e + 365 x'ew'e = 6 v00 = 18495 cm.-1w"e = 673 x''ew''e = 4 A Birge-Sponer extrapolation for the upper state of IF gives D''0(IF) = 1.98 or 2.87 +-0.04 eV, depending on whether the upper state dissociates to excited I and normal F or vice versa. Available evidence favours the lower value for D''o(IF) (= 1.98 +- 0.04 eV), i.e. upper state dissociates to excited I and normal F. By analogy, if we assume the upper state of BrF dissociates to excited Br and normal F, a Birge-Sponer extrapolation gives D''o(BrF) = 2.16 +- 0.02 eV.