Photoelectron Spectroscopy and Structures of X ⋅⋅⋅CH O (X=F, Cl, Br, I) Complexes.

A combined experimental and theoretical approach has been used to investigate X ⋅⋅⋅CH O (X=F, Cl, Br, I) complexes in the gas phase. Photoelectron spectroscopy, in tandem with time-of-flight mass spectrometry, has been used to determine electron binding energies for the Cl ⋅⋅⋅CH O, Br ⋅⋅⋅CH O, and I ⋅⋅⋅CH O species. Additionally, high-level CCSD(T) calculations found a C minimum for these three anion complexes, with predicted electron detachment energies in excellent agreement with the experimental photoelectron spectra. F ⋅⋅⋅CH O was also studied theoretically, with a C hydrogen-bonded complex found to be the global minimum. Calculations extended to neutral X⋅⋅⋅CH O complexes, with the results of potential interest to atmospheric CH O chemistry.