Forty-nine bands arising from
have been detected in the emission spectrum of
from two sources: (i) the reaction of Br or Br
2
with ClO
2
, in which
is populated in the transfer reaction,
3
and (ii) the radiative combination of bromine and chlorine atoms,
5
The populations of the higher levels of
formed in reaction (3) are less than in reaction (5). In reaction (3),
is evidently formed via a triangular transition state similar to that postulated previously; the rate constant,
k
3
, was found to be
The combination of ground state iodine
, and chlorine
atoms was also found to be chemiluminescent in the red and near infrared region, and fifty-seven bands of the system
, with
, have been recorded. The radiative combination of ground-state chlorine atoms has been reinvestigated, and transitions of
from
v
' ≼ 14 have been detected. Combining band head analyses of these emission spectra with previous data, the following constants (in cm
-1
) are reported:
The reasons for the predominant radiation, during atom combination processes, from
type states for Cl
2
and BrCl, and from the
3
II
1
state for ICl, are discussed in relation to Brown & Gibson’s (1932) finding of a maximum in the potential energy curve of
leading to
and
as dissociation products.
Emission spectra in the thermal infrared region
