The quasi-1D conductor (TMTSF)(2)PF6 has a Spin Density Wave transitio
n at 12 K. Previous H-1 NMR studies [1] have shown that the spin-latti
ce relaxation rate, T-1, is finite and Korringa-like inside the Spin D
ensity Wave phase down to about 4 K below which T-1 increases rapidly.
We have measured the linewidth, T-1 and the spin-spin relaxation time
, T-2, of the Se-77 nuclei which, as calculated by bandstructure, are
in closer physical proximity to the electron conduction paths than the
H-1 and, consequently, more strongly coupled to the conduction electr
ons. Using fields up to 24 T, we find that while the lineshape is temp
erature independent inside the SDW phase, the Se-77 T-1 exhibits the s
ame qualitative behavior as the H-1 T-1, and T-2 increases abruptly at
approximate to 4 K. We discuss this result in terms of the Fermi surf
ace of the system.