The electron affinity of thulium has been measured by a technique called laser photodetachment electron spectroscopy. In this technique a gaseous beam of the anions of an element is bombarded with photons from a laser. The photons eject electrons from some of the anions and the energies of the ejected electrons are detected. The incident radiation had a wavelength of 1064 nm and the ejected electrons had an energy of 0.137 eV. Although the analysis is somewhat more complicated, an estimate of the electron affinity can be obtained as the difference in energy between the photons and the energy of the ejected electrons. What is the electron affinity of thulium in electronvolts and in kilojoules per mole?