MICROWAVE SPECTRUM OF TRANS ETHYL METHYL ETHER∗∗^{\ast\ast}

$^{\ast}$This research was made possible by support extended to the University of Norte Dame by the National Science Foundation. $^{\ast\ast}$Alfred P. Sloan Foundation Fellow.Author Institution: Department of Chemistry, University of Notre DameThe microwave spectrum of ethyl methyl ether and deuterated species has been investigated in the region 8 to 30 kMc. For the common isotopic species more than two hundred transitions have been measured. Approximately one hundred of these have been assigned as b-type rotational transitions from the ground state or excited vibrational states of the trans form of ethyl methyl ether. Methyl group $(O-CH_{3})$ tunnelling causes ground-state transitions to appear as doublets, and analysis of the doublet splittings yields a barrier to internal rotation of 2500 cal/mole. The rotational spectra of five excited vibrational states have been assigned. The most interesting assignments are those for the first, second, and third excited states corresponding to skeletal torsion. Assuming that skeletal torsion and methyl torsion are not coupled, the splittings for these excited states should be identical with ground state splittings. Actually, the observed splittings differ in magnitude and for certain excited states in sign as well. An approximate treatment of coupling of methyl and skeletal torsion reasonably accounts for the observed variations in splitting with torsional state

Verrucous Carcinoma of the Tongue: Report of two cases

Two cases of verrucous carcinoma (VC) in the tongue are reported. VC is a variant of well differentiated squamous cell carcinoma. VC grows gradually, has a tendency of local invasion and seldom metastasizes. The patients were treated by laser partial glossectomy. There was neither local recur- rence nor distant metastasis observed. Surgical resection with sufficient safety margin is recom- mended