  In this work we present inelastic neutron scattering experiments which probe
the single ion ground states of the rare earth pyrochlores $R_2$Ti$_2$O$_7$
($R$ = Tb, Dy, Ho). Dy$_2$Ti$_2$O$_7$ and Ho$_2$Ti$_2$O$_7$ are dipolar spin
ices, now often described as hosts of emergent magnetic monopole excitations;
the low temperature state of Tb$_2$Ti$_2$O$_7$ has features of both spin
liquids and spin glasses, and strong magnetoelastic coupling. We measured the
crystal field excitations of all three compounds and obtained a unified set of
crystal field parameters. Additional measurements of a single crystal of
Tb$_2$Ti$_2$O$_7$ clarified the assignment of the crystal field levels in this
material and also revealed a new example of a bound state between a crystal
field level and an optical phonon mode.
