NOTES where X is the spin-orbit coupling constant, and 1 is a correction to the angular momentum about x caused by the crystal field. For those cases where the g values have been very accurately determined the value of 1 has been shown to be quite close to unity. Assuming I = 1.00” and using the value of X = 0.014 eVJ4A can be calculated as 0.78 eV. This is the largest value of A yet observed,ll and it may be compared with the value of A = 0.60 eV for NO on the same zeolite material.’ It is interesting that the crystal field interaction with the weakly adsorbed NO molecule is essentially the same as the interaction with the more tightly bound 02- ion. When O2 was absent from the sample, the spectrum of the yirradiated decationated Y zeolite appeared to be a single weak line, whereas Stamires and Turkevich12 found a six-line spectrum which was ascribed to the interaction of trapped electrons with 27Alnuclei (X2 center). The difference in results can be attributed to the radiation dosages in the two experiments. As Stamires and Turkevich showed, the X2center required an induction dosage of lo6 R while the dosage for the sample without O2was only 0.6 X lo6 R.
Acknowledgment. This work was supported by National Science Foundation Grant GP-8319. (11) I n previous work4 values of A / & A/E, and 1 have been calculated explicitly by using the three principal g values and eq 1-3. A small error in g, and g,, however, will result in a sizable error in A/A, AIE, and 1. For the polycrystalline spectra of 02- on many surfaces, it appears that a better value of A/A can be obtained by taking 1 equal to unity and calculating A/A directly from eq 1. For this reason a better value of A for 02- on ZnO is probably 0.57 eV rather than 0.82 eV.2’4 (12) D. N. Stamires and J. Turkevich, J. Am. Chem. SOC.,86, 757 (1964).
On the Nature of the Products of y Radiolysis of Aerated Aqueous Solutions of Benzene
by T. K. K. Srinivasan, I. Balakrishnan, and M. P. Reddy CommunicationNo. 1891 from the National Chemical Laboratory, Poona-8, India (Recehed November 4, 1068)
I n the y-radiolysis of aerated aqueous solutions of benzene, products other than phenol have been variously described as mucondialdehyde,l a compound of unknown identity which behaves like a phenol,2 and an acidU3 Some conclusions regarding this problem are submitted below. 1. The freshly irradiated solution (neutral a t the start) shows strong absorption maxima at 268 and 345 mp. Three ether extractions reduce exclusively the maximum a t 268 mp and the resulting aqueous layer has a spectrum which is virtually unaffected by subsequent
207 1 ether extraction and shows the p H dependence so meticulously described earlier.2 Bicarbonate washings of the ether layer show hardly any uv absorption and do not yield any appreciable amount of precipitate of hydrazone with dinitrophenylhydrazine reagent (DNPH). After subsequent alkali washing the ether layer shows only uv absorption characteristic of remnants of benzene. After acidification the alkali washings show the uv spectrum of phenol, with the 268-mp peak corresponding closely to the diminution in this peak of the original irradiated solution as a result of ether extraction. The solution couples with p-nitrobenzenediazonium chloride (PNDC) and the dye has an ir spectrum identical with that of the dye obtained with a solution of phenol. 2. The aqueous layer after ether extraction, with two strong nearly equal uv peaks at 268 and 345 mp a t neutral pH, upon acidification to p H
