Bis(pentafluorobenzoy1) peroxide has been prepared by treatment of pentafluorobenzoyl chloride with alkaline hydrogen peroxide. It reacted with hexafluorobenzene, pentafluorobenzene, and benzene to give low yields of fluorinated biphenyls and, in each case, pentafluorophenyl pentafluorobenzoate, also in low yield.
also, the 2-5 F-F couplings are large (26)(27)(28)(29)(30)(31).on the basis of previous work5 on polyfluoroalicyclics. This thiolen (I) must then be destroyed by the molten alkali. The minor mode of dehydrofluorination of thethiolan (11) would involve an or-fluorine; the 2-thiolen thus produced could then further dehydrofluorinate only to t e trafluoro t hiophen. The unf avour able elimination of the or-fluorine would be expected to occur more at high
SummaryThe probability distribution of i<;mization energy in a sodium iodide crystal 2·5 em long by 2·5 em diameter due to the absorption of 18 MeV quanta has been calculated taking account of side escape of electrons from the crystal due to multiple scattering. The results confirm the conclusions of the authors' earlier work.
must cross the dotted line twice. Calculation showed that this arrangement of optics enabled us to compensate sufficiently for the chromatic aberration caused by the Maxwellian distribution, so that we were able to obtain an effective solid angle of (5X 10~5) 4x steradians for flopped atoms reaching the detector from the oven and having a kinetic energy between 300 °K and 1200°K.A point on a resonance curve is taken by inserting a copper button in the position shown in Fig. 1. We collect for 5 min and then count for 5 min with a 2x Geiger counter. A typical resonance for Cu 64 is shown in Fig. 2. The spin of Cu 64 was found to be 1; a tentative FREQUENCY IN MC FIG. 2. Typical Cu 64 resonance curve.value for the hyperfme splitting is 1278±20 Mc/sec. Because of a dependence, which is not understood, of the line center upon the rf power level, at present we cannot say what the sign of the moment is. Using the hyperfme splitting of 0.195 cm" 1 observed spectroscopically by Ritschl, 3 an average of the gyromagnetic ratios of Cu 63 and Cu 65 , 4 and the Fermi-Segre formula, 6 we obtain for the magnetic moment of Cu 64 , |M|=0.40zb0.05nm.A definitive interpretation must await the determination of the sign of the moment.The spin of Ag m is \; a tentative value of the hyperfine splitting is 2180±100 Mc/sec. Using the data of Wessel and Lew 6 on the hyperfme splitting of Ag 107 and Ag 109 , the nuclear magnetic moments measured by Sogo and Jeffries, 7 and the Fermi-Segre formula, we obtain for the magnetic moment of Ag 111 |Ml==0.144±0.007nm.This confirms the spin assignment of McGinnis, 8 and gives further evidence that the addition of two neutrons does not substantially change the nuclear state.We are indebted to Professor Donald R. Hamilton for suggesting the possibility of constructing a focusing atomic beam apparatus and for his continued advice throughout the conduct of the experiment. We also wish to express our thanks to R. D. Petti and R. L. Christensen for their help in constructing the apparatus and taking data. A more complete report on the apparatus and further measurements now in progress will be submitted in the near future. R ESONANCE absorption of gamma radiation was detected by Moon and Storruste 1 in the scattering of Hg 198 radiation by the same nuclei. A high linear speed, mechanically attained, compensated for energy lost to recoil in emission and absorption. In this case, however, Doppler broadening due to thermal motion greatly exceeded the level width.The occurrence of resonance absorption by individual levels in light nuclei has been inferred by Haslam et al. 2 from discontinuities in the slope of the betatron excitation curve for the reaction 0 16 (Y,;Z)0 15 . Some uncertainty remains in this interpretation, however, owing to the energy spread in the betatron radiation.This note reports preliminary experiments using gamma radiation from the reaction Li 7 (^,7)Be 8 . The photonuclear reaction O u (y,n)0 lb was chosen for investigation because it has recently been the subject of a careful betatro...
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