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We review the reactions between carbon chain molecules and radicals, namelyCn, CnH, CnH2, C2n+1O, CnN, HC2n+1N, with C, N and O atoms. Rate constants andbranching ratios for these processes have been re-evaluated using experimentaland theoretical literature data. In total 8 new species have been introduced,41 new reactions have been proposed and 122 rate coefficients fromkida.uva.2011 (Wakelam et al. 2012) have been modified. We test the effect ofthe new rate constants and branching ratios on the predictions of gas-grainchemical models for dark cloud conditions using two different C/O elementalratios. We show that the new rate constants produce large differences in thepredicted abundances of carbon chains since the formation of long chains isless effective. The general agreement between the model predictions andobserved abundances in the dark cloud TMC-1 (CP) is improved by the new networkand we find that C/O ratios of 0.7 and 0.95 both produce a similar agreementfor different times. The general agreement for L134N (N) is not significantlychanged. The current work specifically highlights the importance of O + CnH andN + CnH reactions. As there are very few experimental or theoretical data forthe rate constants of these reactions we highlight the need for experimentalstudies of the O + CnH and N + CnH reactions, particularly at low temperature.

The gas-phase chemistry of carbon chains in dark cloud chemical models