1/f fluctuations in LiCl solution

Intensity fluctuations of scattered light of an Ar+ laser incident on a LiCl solution are measured. Power spectral density of the ratio of outputs of two photomultipliers shows a 1/f-like dependence in the lower-frequency region. Dissolved LiCl raises the level of 1/f fluctuations from that for pure water. Above the molar ratio 0.2 of Li ions to water molecules the fluctuation rapidly decreases. The 1/f level dependence on the concentration of Li ions is semiquantitatively explained by taking the cluster structure into account.