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