An extensive evaluation is presented of the available gas phase chemical kinetic rate constants for the interactions of the low lying electronic states of several atoms and molecules with numerous collision partners. These include the following excited states: C(21D2,21S0), N(22D3/2,5/2,22P1/2,3/2), P(32D3/2,5/2,32P1/2,3/2,), S(31D2,31S0). Se(43P0,41D2,41S0), Te(53P1,0,51D2,51S0), CO(a3à,aââ¬Â²3ã+,d3Ãâ,e3ãâËâ,A1à), CS(a3à,A1à), OH(A2ã+), OD(A2ã+), O2(c1ãu âËâ,C3Ãâu,A3ãu +,B3ãu âËâ), and S2(a1Ãâg,b1ãg +,A3ãu +, B3ãu âËâ). Wherever possible, recommended values are suggested. Much of the data refers only to room temperature. To facilitate the evaluation, collisionââ¬Âfree radiative lifetimes often have been required. These also have been evaluated and are presented. The mechanisms of the interactions and the various potential kinetic channels are discussed. These include such processes as chemical reactions, electronic quenching to the ground electronic state, electronic cross relaxation to an adjacent excited state, and for molecules, vibrational and rotational relaxation processes within the excited state. A complete coverage of the literature published prior to 1978 has been attempted. © 1979, American Institute of Physics for the National Institute of Standards and Technology. All rights reserved.