Non-adiabatic direct dynamics calculations were carried out to investigate the radical and molecular decomposition channels of formic acid. The calculations show, in agreement with experiment, that the HCO + OH dissociation channel accounts for similar to 70% of the product yields. In addition, the molecular eliminations of CO and CO2 are minor channels, with a CO/CO2 branching ratio that depends on what isomer is initially excited to the S-1 state. This result is also in qualitative agreement with experimental results in an Ar matrix environment. (c) 2005 Elsevier B.V. All rights reserved.