  Low energy Raman continuum and the redistribution of the continuum to a peak
(2\Delta-peak) in the superconducting state have been studied in
Tl-Ba-(Ca)-Cu-O superconductors with single (Tl-2201) and double (Tl-2212)
CuO_2 layer. The 2\Delta/k_BT_c ratios in A_1g and B_1g symmetries are larger
for Tl-2212 than for Tl-2201. The B_1g/A_1g gap ratio is also larger in
Tl-2212. The A_1g intensities of the continuum and the 2\Delta-peak are
significantly weaker than the B_1g intensities in Tl-2201, but are comparable
in Tl-2212. This shows that the Coulomb screening is much stronger in Tl-2201.
  The change from Tl-2201 to Tl-2212 of the normalized A_1g 2\Delta-peak
intensity is identical within experimental error to that of normalized A_1g
continuum intensity. This suggests that the excitations forming the
2\Delta-peak and the continuum couple to light by the same mechanism.
