Abstract
Neutron-rich light nuclei and their reactions play an important role for the creation of chemical elements. Here, data from a Coulomb dissociation experiment on 20,21N are reported. Relativistic 20,21N ions impinged on a lead target and the Coulomb dissociation cross section was determined in a kinematically complete experiment. Using the detailed balance theorem, the 19N(n, γ) 20N and 20N(n, γ) 21N excitation functions and thermonuclear reaction rates have been determined. The 19N(n, γ) 20N rate is up to a factor of 5 higher at T < 1 GK with respect to previous theoretical calculations, leading to a 10 % decrease in the predicted fluorine abundance.