The photoelectron spectrum of vinoxide, C2H3O-, at 355 nm is reported, showing photodetachment to both the X(2A‘ ‘) ground and first excited A(2A‘) states of the vinoxy radical. Both direct interpretations and Franck−Condon simulations of the photoelectron spectrum of this simple enolate anion have been used to obtain insights into the energetics and structures of the anion and the ground and first excited state of the neutral radical. Franck−Condon simulations were generated from ab initio geometry and frequency calculations using the CASSCF method and showed good agreement with the vibrational structure visible in the experimental spectrum. The electron affinity (E.A.exp = 1.795 ± 0.015 eV; E.A.calc = 1.82 eV) and separation energy of the ground and first excited states (T 0,exp = 1.015 ± 0.015 eV; T 0,calc = 0.92 eV) obtained from the ab initio calculations are in good accord with the experimental values.

The photoelectron spectra of the trifluoromethyl anion, CF3 -, at 355 and 258 nm are reported. Simulation of the partially resolved vibrational structure is used to extract the adiabatic electron affinity, AEA[CF3] = 1.82 ± 0.05 eV. The heat of formation for the trifluoromethyl anion derived from the adiabatic electron affinity (Δ [CF3 -] = −153.4 ± 1.5 kcal/mol) is compared to the high-accuracy “isodesmic bond additivity corrected” (BAC) complete basis set (CBS-Q) theory prediction (Δ [CF3 -] = −152.6 kcal/mol). We find the CBS-Q prediction of Δ [CF3] = −112.1 kcal/mol, after BAC, to be in excellent agreement with the most recent experimental determination of the radical heat of formation. The photoelectron angular distribution at 355 nm was also extracted from the photoelectron image, revealing p wave photodetachment with an energy-averaged anisotropy parameter of β = 1.5 ± 0.1.

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A new apparatus designed to accelerate/decelerate and study the surface impact phenomena of charged aerosols and nanoparticles over a wide range of mass-tocharge (m/z) ratios and final velocities is described. A nanoparticle ion source coupled with a linear electrostatic trap configured as an image charge detection (ICD) mass spectrometer allows determination of the mass-to-charge ratio and the absolute charge and mass of single nanoparticles. A nine-stage linear accelerator/ decelerator is used to fix the final velocity of the nanoparticles, and in the results reported here the coefficient of restitution for polystyrene latex spheres (PSLs) impacting on silicon is measured using ICD techniques. To enable this apparatus to study a wide range of m/z, the data acquisition system uses a transient digitizer interfaced to a field-programmable gate array module that allows real time calculation of m/z and determination of the pulse sequence for the linear accelerator/decelerator. Electrospray ionization of a colloidal suspension of PSL spheres of 510 and 990 nm has been used to demonstrate acceleration and deceleration of charged nanoparticles and the resolution of the apparatus. Measurements of the coefficient of restitution for PSLs on silicon over the range 10-400 m/s are consistent with previous studies.