| dc.description |
The emission spectrum of SiF has been examined in the Schumann and infra-red regions. The system B-A (ν<sub>0, 0</sub> = 11850.8 cm<sup>-1</sup>) is strong, and rotational analysis shows that both states are <sup>2</sup>Σ. A new rotational analysis of the 0, 0 band of the α-system, A-X<sup>2</sup>π, although in substantial agreement with earlier work, confirms the view that state A is <sup>2</sup>Σ<sup>+</sup>, and not <sup>2</sup>π (case-b), as has previously been supposed. Violet degraded bands which have tentatively been ascribed to five systems, all with X<sup>2</sup>π as the ground state, are found, partly superimposed, in the region 51 000 to 53 500 cm<sup>-1</sup>. Three of the excited states of SiF appear to form a Rydberg series of <sup>2</sup>Σ<sup>+</sup> states leading to the ground state... π<sup>4</sup>σ<sup>2</sup>, <sup>1</sup>Σ<sup>+</sup> of SiF<sup>+</sup>. The ionization potential is found to be 7.2<sub>8</sub> eV. Evidence about the dissociation energy is briefly considered; the best value seems to be D<sub>0</sub>double prime(SiF) similar 125 kcal. |
