We study the properties of charmonium states at finite temperature in
quenched QCD on large and fine isotropic lattices. We perform a detailed
analysis of charmonium correlation and spectral functions both below and above
Tc. Our analysis suggests that both S wave states (J/ψ and ηc)
and P wave states (χc0 and χc1) disappear already at about 1.5Tc. The charm diffusion coefficient is estimated through the Kubo formula and
found to be compatible with zero below Tc and approximately 1/πT at
1.5Tc≲T≲3Tc.Comment: 32 pages, 19 figures, typo corrected, discussions on isotropic vs
anisotropic lattices expanded, published versio