Chemical Physics Letters, Vol.326, No.1-2, 58-64, 2000
Low temperature phase transition in n-pentane C-60 clathrate: a Raman scattering study
We present results on Raman scattering from a C-60.n-pentane (C-60.(n-C5H12)(0.88)(C7H8)(0.05)) clathrate crystal in the range 20-300 K. The Raman intensity, in particular of the H-g modes, increases several times with lowering temperature below 160-200 K accompanied by significant reduction of the linewidths. The onset of this peculiar temperature behavior correlates with the reported phase transition in n-pentane clathrate. We argue that these findings give a Raman scattering signature for a low-temperature orientational phase transition in C-60.n-pentane similar to that observed for solid C-60.