Quantum chemical calculation of the barrier for tunneling of hydrogen in hydrogen abstraction from methane by methyl

An adiabatic reaction path for hydrogen abstraction from methane by methyl is computed by quantum chemical methods and then symmetrized by properly defining the reaction coordinate. The theoretical barriers are then fitted with the barriers defined by the parabolic and Eckart functions. Rate constants for the hydrogen and deuterium‐abstraction processes via tunneling at low temperatures are then computed.