Variational calculation of the energy levels for the tdμ ion

We present variational calculations of the energy levels of the tdμ ion relevant for muon-catalyzed fusion. We used very large generalized Hylleraas basis sets. For all the levels the results are better than literature data. For the most important, weakly bound state of tdμ we obtained a binding energy of 660.01 meV which we estimate to be accurate to about 0.1 meV. For the remaining states the energies converge much faster and we were able to achieve accuracy of about 1 {μ}eV or better.