A strong visible line in the spectrum of W11

We have investigated the visible spectrum of W11+ and found a very strong line at the wave length of 527.61 nm from the 4f135s25p2 (2F7/2-2F5/2) transition. We show that this line is strong since the excitation energy of the upper level opens up the possibility to capture a large population. We discuss the possibility that this strong line could be the unknown line seen in charge exchange spectra recorded at the JET fusion facility.