Isotope shift of the electron affinity of carbon measured by photodetachment microscopy

The electron affinity of carbon is measured on a beam of C- by photodetachment microscopy, with a precision increased by one order of magnitude with respect to the last measurement. Isotopes 12 and 13 are used in succession, which makes it possible to determine the isotope shift of the electron affinity of carbon. The obtained result, about -7.3(6)m-1, corroborates recent calculations of this shift. The electron affinities of C12 and C13 are 1017970.5(10) and 1017963.3(10)m-1, i.e., 1.2621226(11) and 1.2621136(12) eV, respectively.