Heat of Formation. Partition Function. Equilibrium Constant

Heat of Formation. Partition Function. Equilibrium Constant 

AtHo=1219 2 kJ/mol (converted to AfH 98=1225 2 kJ/mol by [21,39]) follows from the threshold energy of PH Ions measured upon photolonizatlon of PH3 [4]. This confirms the earliest mass-spectrometric result, AfH =1218 kJ/mol [2]. An estimate, AfHo=1221 20 kJ/mol, is based on the ionization potential and the dissociation energy of the PH molecule [12]. 

Polynomial expansions of the partition function and the equilibrium constant between 1000 and 10000 K, based on the spectroscopic data compiled by Huber and Herzberg [20], are of astrophysical Interest [40]. 

The only observed electronic transition of PH and PD is the A 2A-X 2] transition lying in the violet and near UV between 450 and 360 nm. 

The A 2A- X 211 Emission Spectrum. The first time, the A X emission spectrum was excited in a hollow-cathode discharge through helium that contained small amounts of hydrogen and phosphorus vapor. A system of three red-degraded bands at 422.8, 385.4, and 356.7 nm was Identified with the v = 0- 1, 0 0, and 1 0 bands. Their rotational and fine structures are those expected for a transition, where the upper state approaches 

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