Modification of the rate of β-decay by chiral molecular environment

The radioactive isotope 32P in the form of phosphoric acid (H332PO4) and 22Na in the form of sodium chloride (22NaCl), were dissolved in R and S mirror image chiral solvents of 2-phenylbutyric acid (PBA) and diethyltartrate (DET). Then their decay rates were determined and compared to each other, to their decay rates in water and to their decay rates in racemic mixtures. It was found that 32P decayed significantly faster if dissolved in R-PBA than in S-PBA. Similarly, 22Na decayed significantly faster if dissolved in R-DET than in S-DET. Evidently the decay rates are sensitive to the right- and left-handed potential fields of the solvent molecules. However, the decay rate of 32P was insensitive to the chiral senses of the DET solvents. Similarly, the decay rate of 22Na was insensitive to the chiral senses of the PBA solvents. This can be tentatively explained by the interactions between the solvents and the solutes. It was also observed that in the first ten percent of the half-life time the decay of 32P and particularly the decay of 22Na often showed some deviation from the exponential behavior. This effect is chirality-dependent. (author)