NF(b Superscript 1 Sigma +) from Discharge-Initiated NF(a1 Delta) and Chemical O2(a1 Delta g)

摘要

Chemically generated molecular oxygen (a superscript 1 delta g) was used to excite nitrogen fluoride (a superscript 1 delta) to nitrogen fluoride (b superscript 1 sigma +) in a vacuum flow system, NF(a) being produced by the reaction of discharge-generated D atoms with nitrogen difluoride radicals. Maximum concentrations of the NF a and b states were 5 x 10 to the 14th power and 7 x 10 to the 12th power/ccm respectively. The latter value is too low to support a blue-green laser based on nitrogen fluoride (b superscript 1 sigma +). A complex kinetic model was developed involving 14 known elementary reactions. Using our experimental conditions as input, the coupled rate equations from this model were numerically integrated to yield rate constants for the forward and reverse O2(a) + NF(a) reaction (6.7 and 1.3 x 10 to the minus 14th power ccm/molecule/s respectively), and for the quenching of NF(a) and NF(b) by water vapour (4 and 5 x 10 to the minus 13th power ccm/molecule/s respectively). The kinetic model shows that a very fast reaction from NF(a) to NF(b) is required in order to achieve a population inversion between NF(b) and the ground state NF(X). Excited atomic iodine appears to be a better candidate than O2 (a superscript 1 delta g) for generating high densities of NF(b).