Californium CAS NO.7440-71-3

Reference Californium-252 fission fragment ionization mass spectrometry of chlorophyll a Californium-252 fission fragment ionization mass spec…

Reference Californium-252 fission fragment ionization mass spectrometry of chlorophyll a Californium-252 fission fragment ionization mass spectrometry of chlorophyll a. Chait, B.Some chemicals with cas registry numbers like 479-61-8 are also used. T.; Field, F. H. (Rockefeller Univ., New York, NY 10021, USA). J. Am. Chem. Soc., 106(7), 1931-8 (English) 1984. CODEN: JACSAT. ISSN: 0002-7863. DOCUMENT TYPE: Journal CA Section: 73 (Optical, Electron, and Mass Spectroscopy and Other Related Properties) Section cross-reference(s): 71 The title study was made by using a time-of-flight mass spectrometer, placing primary emphasis on fragmentation reactions and rates. The mass spectrometer was modified so that segmented fields with segments of different magnitudes could be applied in the ion acceleration region and regarding potentials in the region between the flight tube and the ion detector. Methods using these retarding potentials were developed for detg. the identities of fragmentations in the flight tube and for measuring the rate consts. of fragmentations occurring in the ion acceleration region. Pos. and neg. spectra were detd. with and without retarding potentials at the end of the flight tube. Extensive amts. of fragmentation occur both close to the sample foil (prompt fragmentation) and in the flight tube. For example, 98.9% of the pos. mol. ions from chlorophyll a enter the flight tube fragment before reaching the detector. In the spectra with retarding potential applied, M+× and (M + H)+ ions are the ions in the pos. mol.-ion region, and (M - H)-, M-×, and (M + H)- are the ions in the neg. mol.-ion region. Networks of fragmentation paths were deduced from retarding potential measurements. Rate consts. for certain fragmentations are deduced from tails on peaks and from measurements utilizing segmented fields in the ion acceleration region. It is deduced that fragmentations occur with rate consts. ranging from >109 s-1 to 104 s-1. The fission fragment induced fragmentation processes obsd. in Chl a involve many of the concepts embodied in the quasi-equil. theory of mass spectra, e.g., formation of reactant ions with a wide range of energies, which results in a network of sequential and competing unimol. reactions with variable and wide-ranging rate consts.