(SILEX) process, developed by Silex Systems in Australia, has been licensed to General Electric for the development of a pilot enrichment plant. The method uses uranium hexafluoride as a feedstock, and uses magnets to separate the isotopes after one isotope is preferentially ionized. Further details of the process are not disclosed. Quite recently yet another scheme has been proposed for the deuterium separation using Trojan wavepackets in circularly polarized electromagnetic field. The process of Trojan wave packet formation by the adiabatic-rapid passage depends in ultra-sensitive way on the reduced electron and nucleus mass which with the same field frequency further leads to excitation of Trojan or anti-Trojan wavepacket depending on the kind of the isotope. Those and their giant, rotating electric dipole moments are then -shifted in phase and the beam of such atoms splits in the gradient of the electric field in the analogy to Stern–Gerlach experiment. Chemical methods Although isotopes of a single element are normally described as having the same chemical properties, this is not strictly true. In particular, reaction rates are very slightly affected by atomic mass. Techniques using this are most effective for light atoms such as hydrogen. Lighter isotopes tend to react or evaporate more quickly than heavy isotopes, allowing them to be separated. This is how heavy water is produced commercially, see Girdler sulfide process for details. Lighter isotopes also disassociate more rapidly under an electric field. This process in a large cascade was used at the heavy water production plant at Rjukan. One candidate for the largest kinetic isotopic effect ever measured at room temperature, 305, may eventually be used for the separation of tritium (T). The effects for the oxidation of tritiated formate anions to HTO were measured as: {| |- | k(HCO2−) = 9.54 M−1s−1 | k(H)/k(D) = 38 |- | k(DCO2−) = 9.54 M−1s−1 | k(D)/k(T) = 8.1 |- | k(TCO2−) = 9.54 M−1s−1 | k(H)/k(T) = 305 |} Gravity Isotopes of carbon, oxygen, and nitrogen can be purified by chilling these gases or compounds nearly to their liquefaction temperature in very tall () columns. The heavier isotopes sink and the lighter isotopes rise, where they are easily collected. The process was developed in the late 1960s by scientists at Los Alamos National Laboratory. This process is also called "cryogenic distillation". The SWU (separative work unit) Separative Work Unit (SWU) is a complex unit which is a function of