After a brief listing of the available structural, spectroscopic, and thermochemical data for gaseous formic acid, we summarize the results of quantum mechanical computations of minimum energy structures and standard entropies for the ring and chain dimers and for the monomer. The computed increments in thermochemical parameters for Intercanversfdns between these species are compared with values derived from measured variations of equilibrium constants with temperature. Rate constants were estimated both for the limiting high and low pressure regimes; these relaxation times were computed for several possible mechanisms. At low pressures, the computed activation energy for one of several sequential processes is consistent with that derived from the temperature-dependet relaxation times. (C) 1997 American Institute of Physics.