Photoelectron Spectroscopy and Structures of X‐…CH2O (X=F, Cl, Br, I) Complexes

A combined experimental and theoretical approach has been used to investigate X -… CH 2 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 2 O, Br -… CH 2 O, and I - …CH 2 O species. Additionally, high-level CCSD(T) calculations found a C 2v   minimum for these three anion complexes, with predicted electron detachment energies in excellent agreement with the experimental photoelectron spectra. F -… CH 2 O was also studied theoretically, with a C s hydrogen-bonded complex found to be the global minimum. Calculations extended to neutral X … CH 2 O complexes, with the results of potential interest to atmospheric CH 2 O chemistry.