Isotopic quantum effects in the structure of liquid ethanol

High-energy electromagnetic-radiation-scattering techniques have been used to measure the structural differences between five isotopic samples of ethanol (CH3CH2OH, CD3CD2OD, CD3CH2OH, CH3CH2OD, and CH3CD2OH) at room temperature and ambient pressure. The differences in the X-ray structure factors between several pairs of isotopes, ΔSX(Q), are shown to have maximum amplitudes that are on the order of a few percent compared to the total structure factor for CH3CH2OH. Our uncertainties are an order of magnitude smaller than those of early gamma-ray measurements on methanol (C.J. Benmore and P.A. Egelstaff. J. Phys. Condens. Matter, 8, 9429 (1996)). These studies have shown that isotopic structural differences in room-temperature ethanol vary as a function of substitution site and are in qualitative agreement with similar differences found in liquid methanol. PACS Nos.: 61.20-p, 61.25E, 61.10-E