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Electron cyclotron resonance ion source related development work for heavy-ion irradiation tests Rev. Sci. Instrum. 77, 03A316 (2006); 10.1063/1.2163895 Development of the compact electron cyclotron resonance ion source for heavy-ion therapy Rev. Sci. Instrum. 71, 984 (2000)Ion motion in a Penning trap and the electrical signals it can produce have been analyzed for the purpose of identifying the important causes of uncertainty in high-accuracy mass measurements of heavy ions. The role of the azimuthal quadrupole electric field in signal pickup, and its effects on ion motion at the sum frequency of the cyclotron and magnetron motions, have been identified. A useful scheme for calculating the signal strength and strength of the interaction between an applied field and the ion motion has been developed. The important sources of uncertainty in using the sum frequency of the cyclotron and magnetron motions for determining the ion mass are discussed. Particular application is made to the case of cyclotron resonance detection by observation of the time of flight of ejected ions.

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An improved procedure for the synthesis of (N-isocyanimino)-triphenylphosphorane, CϵN-N=PPh 3 (3), is described. The X-ray structure analysis reveals an unusually small N-N=P angle [115.2(2)°] and an N-N bond order of only about 1.5, which indicates considerable CϵN-N --P + participation and electronically more-isolated functional groups (CN, P=N) in the isocyanide than, for example, in the isomeric NϵC-N=PPh 3 (4) [C-N=P = 123.0(4)°, C-N bond order = 2.0]. In order to gain insight into the stereochemical consequences of metal coordination of 3, an X-ray structural study of [Cr-(CO) 5 CϵN-N=PPh 3 ] (5) was also undertaken. Surprisingly, the central bond lengths (C-N, N-N) and angles (C-N-N) remain practically unchanged with noticeable coordination effects occurring only at the periphery of 5, with the N-N-P angle [112.3(2)°] further decreased by 15σ, the elongated (by 7σ) P-N bond, the somewhat shortened (by 4σ) P-C(Ph) bonds and even shorter C-H(Ph) bonds on the one side, and the well-known Cr-C(O) trans contraction on the other. Treatment of 5 or its tungsten derivative with anhydrous Brønstedt and Lewis acids such as CF 3 COOH, HCl, COS, phosgene or,