  The multichannel quantum defect theory (MQDT) in combination with the frame
transformation (FT) approach is applied to model the Fano-Feshbach resonances
measured for $^{7}$Li$^{87}$Rb and $^{6}$Li$^{87}$Rb [Marzok {\it et al.} Phys.
Rev. A {\bf 79} 012717 (2009)]. The MQDT results show a level of accuracy
comparable to that of previous models based on direct, fully numerical
solutions of the the coupled channel Schr\"odinger equations (CC). Here, energy
levels deduced from 2-photon photoassociation spectra for $^{7}$Li$^{85}$Rb are
assigned by applying the MQDT approach, obtaining the bound state energies for
the coupled channel problem. Our results confirm that MQDT yields a compact
description of photoassociation observables as well as the Fano-Feshbach
resonance positions and widths.
