Effect of high hydrostatic pressure on the intramolecular modes of (C59N)(2)

The effect of high pressure, up to LO GPa, on the phonon spectra of azafull erene, (C59N)(2), at room temperature has been investigated by Raman spectr oscopy. At ambient pressure, the Raman spectrum of (C59N)(2) displays eight of the ten molecular modes of C-60 Their Frequencies are close to those of the corresponding modes of pristine Cb, solid. The pressure dependence of the H-g(7), A(g)(2), and H-g(8) phonon frequencies exhibits reversible chan ges in their pressure coefficient in the region 6.0 +/- 0.5 GPa. In additio n, the A(g)(1) breathing mode shows two clear changes in tbe pressure depen dence of the pressure coefficient, one at similar to 3.0 and another at sim ilar to 6.0 GPa. The results are explained by taking into account the press ure dependence of the structural properties of solid (C59N)(2) [S0163-1829( 99)14903-8].