  Physics of supercritical state is understood to a much lesser degree compared
to subcritical liquids. Carbon dioxide in particular has been intensely
studied, yet little is known about the supercritical part of its phase diagram.
Here, we combine neutron scattering experiments and molecular dynamics
simulations and demonstrate the structural crossover at the Frenkel line. The
crossover is seen at pressures as high as 14 times the critical pressure and is
evidenced by changes of the main features of the structure factor and pair
distribution functions.
