Tunneling electron loss from isolated platinum tetrahalide dianions

摘要

Electron detachment from doubly charged anions PtCl_xBr_(4-x)~(2-) to form PtCl_xBr_(4-x)~(2-) (x=0-4) was probed for in a Fourier-transform ion-cyclotron-resonance mass spectrometer at 288 K.The corresponding decay rates were measured as s function of collision gas pressure.In the zero-pressure limit,nonzero unimolecular decay rate constants were pbserved fpr x=4 and 3 (0.273+-0.035 and 0.056+-0.019 s~(-1) for 288 K,respectively).These show a strong temperature dependence suggesting the new phenomenon of blackbody radiation induced tunneling electron loss.Comparison to electron tunneling rates calculated by means of the Wentzel-Kramers-Brillouin approximation using Coulomb barrier properties and electron detachment energies derived from ab initio quantum chemical calculations provides a qualitative rationalization of the observed trends.