MP2 and coupled-cluster calculations were performed to investigate the structure, stability, and properties of the noble gas anions FNgSe (Ng = He-Xe). Similar to the recently investigated congeners FNgO and FNgS , with the only exception of FNeSe , all these species reside into energy minima on the singlet surface. The heaviest FKrSe and FXeSe are also protected by sizable barriers with respect to FSe + Ng and F + Ng + Se(P-3). They are therefore the first predicted examples of metastable krypton-selenium and xenon-selenium molecular species. The lightest FHeSe and FArSe are instead kinetically unstable rather than metastable. (C) 2009 Elsevier B.V. All rights reserved.