Arrhenius and power-law parameters of the Orbach and Raman processes in the temperature ranges 10 K ≥ T ≥60 K as well as 60 K ≥ T ≥ 120 K, respectively. Reported uncertainties are the estimate standard errors from the least squares linear fits.

SMM	U eff/cm−1	τ 0 −1/109 S−1	n	C/10−8 K−n s−1
0	1330 ± 10	360 ± 80	3.368 ± 0.007	1.92 ± 0.04
1	1340 ± 10	190 ± 40	3.5 ± 0.06	0.17 ± 0.04
2	1200 ± 20	40 ± 10	2.81 ± 0.04	75 ± 10
3	1150 ± 10	130 ± 30	3.63 ± 0.06	3.4 ± 0.7