LiI Solution Research Articles

The mechanism of 7Li relaxation in a supercooled aqueous LiI solution

1H, 2D, and 7Li relaxation time measurements in a 6-aquamolal aqueous Lil solution were performed as a function of temperature. By isotopic H/D substitution the 7Li relaxation rate was separated into the dipolar and quadrupolar contributions. At about 180 K, maxima for 1/ T 1 plotted vs 1/ T were obtained. The maximum of the quadrupolar contribution to 7Li relaxation occurs at the same temperature as the maxima obtained for 1H and 2D relaxation, which means that 7Li relaxation is determined by reorientational Brownian motions of the species. This result is compared with the predictions of several recent theories for the quadrupolar relaxation of monoatomic ionic nuclei in electrolyte solutions. The results give support to an electrostatic model.

The Measurement of the Abundance Ratio of Lithium Isotopes using Atlas CH4Mass-Spectrometer.

One drop of 200 mg/ml LiI solution is deposited in the ionization case. Under conditions such that the max peaks of Li/sup 7/ and Li/sup 6/ can be obtained, the peaks due to these isotopes are recorded repeatedly. More than 20 measured values of the abundance ratio in the region around the point on which the ionization current reaches a max are determined, and their average value is assumed as the (true) abundance ratio of the sample used. In order to investigate the difference of anions in the sample, LiCl, LiI, LiNO/sub 3/, and Li/sub 2/SO/sub 4/ were used, and LiI was found to be most suitable. The measured value of the abundance ratio varies according to the type of the ionization case and conditions of the determination. The effect of ionization current is large, and, generally, the measured value of the abundance ratio increases with increasing heating current. The amount of sample, the spotting point, and the measuring time must be constant. In the measurement of relative value, the error is checked within plus or minus 0.1%. (Nucl. Sci. Abstr. Japan, Vol. 2, No. 4)