Controlling achiral and chiral conformations of benzyl alcohol by -halogenation, collisional relaxation and dimerisation.

-Halogenated benzyl alcohol can exist in two different low energy chiral conformations, only one of them with an OH-X contact (X = Cl, Br, I). A third, achiral conformation is enabled by the halogen substitution. We show by IR spectroscopy in supersonic jets that the achiral monomer is less stable than the chiral conformation with OH-X contact, but both can be produced in similar amounts using helium as a carrier gas.