Photoelectron spectroscopy with cm-1 resolution: VO+ benzyl+ toluene+

摘要

Detection of nominal `zero kinetic energy electrons' in resonant two-photon ionization with approximately ega$-1$/ fixed and approximately ega$-2$/ scanned permits photoelectron spectroscopy with 1 - 5 cm$+$MIN@1$/ resolution. We report vibrational bands from 0 - 650 cm$+$MIN@1$/ for benzyl$+$PLU$/-h$-7$/, benzyl$+$PLU$/-$alpha@d$- 2$/, and benzyl$+$PLU$/-d$-7$/. The exocyclic C-C bond of benzyl cation has substantial double bond character. Band assignments from ab initio frequencies illuminate the mechanism of vibronic coupling in the 1$+2$/A$-2$/-2$+2$/B$-2$/ system of neutral benzyl. In toluene$+$PLU$/, we observe internal rotor frequencies that fix the V$-6$/ barrier height of the CH$-3$/ rotation at 20 $POM 5 cm$+$MIN@1$/, which is remarkably low. In VO $YLD VO$+$PLU$/ $PLU e$+$MIN$/, we measure state-to-state relative photoionization cross sections from the intermediate spin- rotational state N$PRM J$PRM to different cation spin-rotation states N$+$PLU$/J$+$PLU$/. Remarkably strong lines corresponding to large changes in angular momentum ($Delta@N $EQ $MIN@6 to $PLU@7 and $Delta@J $EQ $MIN@6.5 to $PLU 6.5) are observed. Accurate values of the adiabatic ionization potentials of each molecule are reported.