Inelastic neutron scattering study of crystalline electric field excitations in the caged compounds <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>Nd</mml:mi><mml:msub><mml:mi>T</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi>Zn</mml:mi><mml:mn>20</mml:mn></mml:msub></mml:mrow><mml:mo> </mml:mo><mml:mrow><mml:mo>(</mml:mo><mml:mi>T</mml:mi><mml:mo>=</mml:mo><mml:mi>Co</mml:mi><mml:mo>,</mml:mo><mml:mo> </mml:mo><mml:mi>Rh</mml:mi><mml:mo>,</mml:mo><mml:mo> </…

We have measured crystalline electric field (CEF) excitations of ${\mathrm{Nd}}^{3+}$ ions in the two-channel Kondo lattice candidates $\mathrm{Nd}{\mathit{T}}_{2}{\mathrm{Zn}}_{20}$ $(T = \mathrm{Co}, \mathrm{Rh}, \text{and} \mathrm{Ir})$ by means inelastic neutron scattering (INS). In INS measurements at 5 K, dispersionless were observed 3.8 and 7.2 meV for $T=\mathrm{Co}$, 3.1 5.8 $T=\mathrm{Rh}$, 3.0 5.3 $T=\mathrm{Ir}$. Analyses temperature dependence spectra confirm that CEF ground states are ${\mathrm{\ensuremath{\Gamma}}}_{6}$ doublet, is a requisite manifestation magnetic effect. For shoulder was 7.7 close to excitation peak centered meV. The attributed bound state low-lying optical phonon excitations.