JMSSJ On-line Abstracts, Vol.47, No.2 (1999)

Gas-Phase Polymerization Reactions Induced by the C₂H⁺_m Ions (m=3-5) in Ethene

Kenzo HIRAOKA,^*a) Takanori KOJIMA, Teruaki SUGIYAMA, and Jun KATSURAGAWA^a) (Faculty of Engineering. Yamanashi University, Takeda-4, Kofu 400-8511, Japan)

J. Mass Spectrom. Soc. Jpn., 47(2), 67-71, 1999

Gas-phase ion-molecule reactions in ethene were measured by using a pulsed-electron beam high-pressure mass spectrometer. All the major ions observed, i.e., C₂H⁺₃, C₂H⁺₄, and C₂H⁺₅, were found to react with C₂H₄ to form polymerized ions. The degree of polymerization increased with decrease of temperature. This is due to the presence of the entropy barrier in the reaction coordinate. When the ethene pressure was increased, the polymerization reactions were greatly suppressed. This is due to the steric hindrance for the polymerization reaction by the formation of cluster ions, i.e., the entropy bottle neck for the formation of polymerized ions becomes narrower by the formation of cluster ions. The chemical reactivity of C₂H⁺₃ was found to be the smallest among three carbocations.

Measurements of Thermodynamic Properties of Iron in Molten Silicon by Knudsen Effusion Method

Takahiro MIKI,^*a) Kazuki MORITA,^a) and Michio YAMAWAKI^b) (^*a)Department of Metallurgy, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan, ^b)Department of Quantum Engineering and Systems Science, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan)

J. Mass Spectrom. Soc. Jpn., 47(2), 72-75, 1999

Metallic impurities in Si will decrease solar cell efficiency to a large extent. To discuss the possibility and efficiency of impurity elimination process, evaluation of thermodynamic properties of impurities in molten silicon are crucial. In the present work, thermodynamic properties of Fe in molten Si were investigated by Knudsen effusion method. The activity coefficients of Fe in molten Si for infinitely dilute solution relative to pure liquid, and self-interaction parameters at 1723-1823 K were determined.

Reflections on Electrospray Mass Spectrometry of Synthetic Polymers

Maya MAEKAWA,^*a) Takashi NOHMI,^a) Dongliang ZHAN,^b) Pauel KISELEV,^b) and John B. FENN^b) (^*a)NOHMI BOSAI Ltd. Research Laboratory, 3-14-4 Nishi Shinjuku, Shinjuku-ku, Tokyo 160-0023, Japan, ^b)Department of Chemistry, Virginia Commonwealth University, 1001 West Main Street P.O. Box 842006, Richmond, Virginia)

J. Mass Spectrom Soc. Jpn., 47(2), 76-83, 1999

Electrospray ions of several samples of poly(ethylene glycol)s (PEGs) were examined and characterized by three different analyzers including two quadrupole mass filters and one ion trap. Also shown are some data obtained by MALDI-TOF. Comparison of the results with those obtained some years ago shows that relatively modest increases in instrument resolving power can greatly change the appearance of a spectrum and increase its information content. However it also seems possible that too much resolving power may actually decrease the accessibility of desired information. Also presented are some results on the effect of polymer solutes on the deformation of droplets subjected to intense electric fields. The observations suggest that such materials may profoundly affect the fundamental processes involved in the formation of solute ions from charged droplets.

Evolution of the Universe and Chemical Reactions in the Dark Clouds

Kenzo HIRAOKA (Faculty of Engineering. Yamanashi University, Takeda-4, Kofu 400-8511, Japan)

J. Mass Spectrom. Soc. Jpn., 47(2), 84-90, 1999

The evolution of the universe was dealt with on the view point of the chemical reactions taking place in the dark clouds in the interstellar medium. The reactions of H atoms with N, C, O, CO, CH₃CN, and C₂ hydrocarbons in solid phase at 10 K were investigated by temperature-programmed mass spectrometry and FT-IR spectroscopy. The reactions investigated led to the formation of organic compounds which are important for the evolution of life. It was found that the solid-phase tunneling reactions taking place on the dust grains at ~10 K play important roles for the chemical evolution in the dark clouds.