Quenching of the 1.0 and 2.3 mgr;m excited electronic states of PuF6at room temperature by selected rare gases and small polyatomic molecules

摘要

The quenching rate constantskqfor the following rare gases and small molecules (He, Ar, Xe, H2, D2, N2, O2, F2, Cl2, HF, CO, CO2, CH4, CHF3, CF4, NO2F, SOF4, SF6, and UF6) are reported in units of cm3moleculeminus;1sminus;1for both the 1.0 and 2.3 mgr;m excited electronic states of PuF6(see Table I). The selfhyphen;quenching rate constants for PuF6at room temperture arekq(1.0 mgr;m) =1.12plusmn;0.01times;10minus;12andkq(2.3 mgr;m)=5.01plusmn;0.11times;10minus;15cm3moleculeminus;1sminus;1. The magnitude of the quenching rate constants for most all of the gases considered above suggest that the dominant process in the collisional deexcitation of excited state PuF@B6(1.0 or 2.3 mgr;m) molecules at room temperature is physical quenching (i.e., Ehyphen;T or electronichyphen;tohyphen;translational collisional energy transfer). Our data also indicate that Ehyphen;V (electronichyphen;tohyphen;vibrational) energy transfer is responsible for the efficient quenching of electronically excited PuF6by H2, HF, CH4, and CHF3. There is also evidence from our data that the efficient quenching of the excited states of PuF6by ground state PuF6molecules proceeds via resonant energy transfer.