Structure and Raman scattering of Cs3C60 under high pressure

Raman scattering is studied for a pressure-induced superconductor Cs3C60 in a pressure region from 1 bar to 62 kbar. The center Frequency omega(0) for H-g(1) and H-g(2) Raman peaks increase by applying pressure, but the Increase shows a saturation in the high-pressure region. On the other hand, the omega(0) for A(g)(1) and A(g)(2) modes increase monotonically in all pressure regions. The electron-phonon coupling constant for Cs3C60 shows a rapid decrease up to 30 kbar and an increase above 30 kbar. This result may be associated with a transformation From a multiphase (body-centered orthorhombic and A 15 phases) to a single phase around 20 kbar. X-ray powder diffraction pattern at 11 K under a pressure of 40 kbar shows that a superconducting phase for Cs3C60 is body-centered orthorhomhic.