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The reactions of ions in the series PH+n (n=0 to 4) have been studied at 300 K with CH3NH2, PH3, NH3, CH3CCH, H2S, C2H4, CH3OH, COS, C2H2, O2, H2O, CH4, HCN, CO2, CO, and H2 using a selected ion flow tube (SIFT) apparatus. The majority are fast binary reactions, the measured rate coefficients, k, being close to the respective collisional values, and for reactions involving polyatomic reactant molecules multiple product ions are observed. Most reaction mechanisms are represented in this large number of reactions including charge transfer, proton transfer, atom abstraction and especially evident is phosphorus atom insertion in which product ions such as HnPN+, HnPO+, HnPS+ and HnCmP+ are formed. The reactions of the PH+n ions (n=0 to 2) with CO2, CO, and H2 proceed by the process of ternary association except for the P+ reaction with CO2, in which PO+ is formed in a fast binary reaction. PH+4 reacts only with CH3NH2 and NH3 by fast proton transfer, a process which is always rapid when it is exothermic. Upper limits to the heats of formation of HPO+, H2PO+, PC2H2+ and HCP have also been deduced from their observation as products of some of the reactions.

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We report the first observation, to our knowledge, of three-level laser oscillator operation in a crystal activated with Mn5+. The material is Mn:Ba3(VO4)2 which exhibited laser oscillation at room temperature under pulsed 592 nm excitation. The laser emission occurs at 1181 nm with a threshold of 0.3 J/cm2. Spectroscopy indicates that this material operates as a three-level system on the 1E to 3A2 transition of the Mn5+ ion with tetrahedral coordination. The strong, broad absorption bands and 0.43 ms room-temperature lifetime make this system very promising for flash lamp AlxGa1−xAs diode pumping.

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