Displaying IR and Raman spectra of benzene

Hello,

I want to compare the IR and Raman spectrum of benzene(liquid) between experiment and simulation result. There are two modules I use, Dmol3 and CASTEP.

Although I tried to follow the instuctions of MS online Help, I still faced some problems:

Dmol3:

After sketching a benzene and performing Dmol3 geometry optimization calculation(Quality : fine / Functional : GGA PBE / check Frequency (properties)), I displayed a Raman spectrum(attachment) with Dmol3 analysis.

However, it didn't seem to match up with the expriment spectrum from database. Is any mistake step in the calculation?

CASTEP:

Errors and failure appeared all the time. I tried to build a amorphous cell to request polarizability, IR and Raman spectra, but it didn't work.

Is it possible that CASTEP is used to explore the properties of "crystals and surfaces" in materials, so it can't deal with liquid benzene?

Thanks.