Abstract: Iodine monofluoride is a potential visible lasing medium due to its ease of emission on IF(B→X) transition in 450-750 nm with favorable Franck-Condon factors. Nevertheless, the production of IF(B~3Π_0~+)) by a chemically-pumped pro- cess involving energy transfer has scarcely been investigated~[1-4].
We have succeeded in producing NF(b~1∑~+)) species directly in the F-F_2-NH_3 system via a supersonic regime. It is of interest to extend our studies to ob- tain IF(B~3Π_0~+) by energy transfer between NF(b~1∑~+) and ground state IF, in the hope of developing a visible chemical laser.
As in reference[5], the experimental arrangement cosists essentially of a remodeled supersonic c_w HF chemical laser, a 0.3 M polychromator and an optical multichannel analyzer. F_2, D_2 and CF_3I are burned in a combustor to produce F atoms and IF molecules. The supersonic stream of F+F_2_IF flowing out of the nozzle bank is then mixed with a subsonic stream of NH_3 in a 30 cm long reaction zone.
The IF(B→X) emission was observed from the OMA recordings in the range of 450 to 750 nm with 33 band heads as shown in Fig.2.
Fig.3 shows the distribution of NH_2~*, NH~*, NF(b) and IF(B) emissions along X.
The production of IF(B) may include the following steps:
F+NH_3→NH_2~*+HF(v≤2) (1)
F+NH_2~*→NH~*+HF(v≤4) (2)
F_2+NH~*→NF(a)+HF (3)
NH(a)+HF(v)→NF(b)+HF (4)
NH~++IF(X)→NH(X)+IF(B) (5)
NF(b)+IF(X)→NF(X)+IF(B) (6)
The initial rise in IF(B), as shown in Fig.3, is consistent with[5]. The continued rise in IF(B) is probably due to excitation by NF(b) which rises more steeply than NH~* decays with distance. Unless IF(B) is excited by another species it cannot decrease while NF(b) increases unless IF(X) is being chemically removed.