We have measured the angular dependence and total intensity of light scattered by carbon dioxide near its critical point, shown that the Ornstein-Zernike theory is inadequate, and determined the temperature dependence of the isothermal compressibility $K_T$ and the long-range correlation length $\xi$. The exponents describing the divergences of $K_T$ and $\xi$ above the critical temperature are $\gamma =1.219\mathrm{}\pm 0.01$ and $\nu =0.633\mathrm{}\pm 0.01$, respectively. The exponent describing the departure from the Ornstein-Zernike theory is $\eta =0.074\mathrm{}\pm 0.035$.

• Received 6 July 1971

DOI:https://doi.org/10.1103/PhysRevLett.27.841