Low lying electronic states of rare gas-oxide anions: Photoelectron spectroscopy of complexes of O − with Ar, Kr, Xe, and N 2

Articles you may be interested inIndirect dephasing model and librovibrational spectra of diatomics trapped in rare gas matrices. Application to the case of CO/Ar Absorption and emission spectra of Li atoms trapped in rare gas matrices Absorption and emission spectra of K atoms trapped in raregas matrices Absorption and emission spectra of Na atoms trapped in raregas matricesThe emission spectrum of the Cameron bands (a 3 n --+X 1 .l" +) of CO molecules trapped in solid Ne, Ar, and Kr has been studied using Xe resonance lamp excitation (A = 147 nm). The lifetime of the a 3n state has been measured in solid Ne and found to be 90 msec. The decay time of this state is exponential within the range of experimental errors. The lifetime has been calculated assuming spin-<>rbit mixing between '.l" + and 3n 0 states, and found to be 94 msec for J = O. The lifetime values in Ar and Kr matrices are found to be 7.2 and < I msec, respectively; this is consistent with the matrix shifts in solid Ne, Ar, and Kr, which for the ()...{) bands have been found to be -305, -946, and -2812 cm -I , respectively.

The methanol photodecomposition quantum yield increases with the addition of different foreign gases (alkanes, rare gases, C 0 2 , SF6). Whereas the methanol absorption spectrum presents a continuum in the 1850 8, region, the added gas effect implies that collisions are involved in reaching the dissociative state. This apparent contradiction between photochemical and spectroscopic data leads to the postulate of the existence of a collision-induced predissociation. The efficiency of the different gases in promoting the predissociation correlates with their polarizability. In absence of spin-orbit coupling, the collision-induced predissociationc an be explained on the basis of a van der Wads interaction. With Kr and Xe as added gases, spin-orbit coupling is an additional dissociative channel.

The vuv photodissociation of OCS in an argon matrix at 5 K has been shown to yield S(1S) atoms. The S(1S –1D) emission is observed only during the irradiation and does not appear when CS2 is photolyzed under the same conditions. However, in both cases the thermoluminescence which follows an increase of the matrix temperature is due to the S2(B 3Σu−→X 3Σg−) radiative transition. This substantiates the fact that S atoms do indeed diffuse in an argon matrix already at 6 K. Furthermore, the (a 3Π→X 1Σ+) emission of CS is observed both during the CS2 irradiation and as thermoluminescence. This last observation suggests that C atoms can also diffuse under these conditions at about the same rate as the diffusion rate of N atoms in N2 matrix, measured by Brocklehurst and Pimentel.

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