Table 1.

Grüneisen parameter and its projection

Element	${\overline{\gamma }}_{TA}$	${\overline{\gamma }}_{TA\prime }$	${\overline{\gamma }}_{LA}$	${\overline{\gamma }}_{aver}$	${\overline{\gamma }}_{TO}$
Total	1.69	1.47	1.19	1.45	3.32
Cu1	0.638	0.554	0.407	0.533	0.972
Cu1x	0.058	0.026	0.081	0.055	0.110
Cu1y	0.107	0.142	0.058	0.102	0.140
Cu1z	0.489	0.395	0.295	0.393	0.747
Cu2	0.294	0.251	0.217	0.254	0.545
Se1	0.297	0.250	0.189	0.245	0.524
Se2	0.239	0.211	0.157	0.202	0.390
Sb	0.241	0.212	0.239	0.231	0.948

The average values are only for the acoustic branches. The Grüneisen parameter of the transverse optical (TO) mode is also shown.