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DISCUSSION 



Platt: This is a tangential comment which may be relevant to the paper by Professor 

 Gordy and that by Professor Platzman and Professor Franck. It is that Dr. Meyerson* 

 has recently done some extremely beautiful work on species of various mass fragments that 

 break up during their flight time in the mass spectrometer, and by isotopic substitution 

 experiments, checking the species that come out, he has proved that when isopropylbenzene 

 is bombarded with 50-volt electrons, the side group is changed to a cyclopropyl group in which 

 all three carbons are equivalent. He has also proved that if a molecule like toluene is bom- 

 barded, the decay in flight indicates the existence of a species of the form of a tropylium ion, 

 a Cy ion in which again all the carbons are equivalent. Similar results are obtained down to 

 zero excess electron energy. 



* P. N. Rylander, S. Meyerson, and H. M. Grubb, "I. The Cationated and Cyclo- 

 propane Ring" /. Amer. Chem. Soc. 78, 5799-5802 (1956): Organic ions in the gas phase. 

 II. The tropylium ion. J. Amer. Chem. Soc. 79, 842-846 (1957). See also later papers of 

 this series by same authors in J. Chem. Phys. and /. Phys. Chem. 



