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101.
Methane derivatives of CH(3)-X (X: H, F, Cl, Br, I, and CN) were ionized and fragmented by an intense femtosecond laser with a 40 fs pulse at 0.8 microm in intensities of 10(13)-10(15) W cm(-2). The curves of the ionization yields of CH(3)-X versus laser intensities have been found to be fitted with an atomic ionization theory (the theory of Perelomov, Popov, and Terent'ev) that has been established to reproduce experimental results well for rare gas atoms. The saturation intensities have been reproduced within a factor of 1.6 of the calculated ones. For molecules with low ionization potentials such as amines, another atomic ionization theory (the theory of Ammosov, Delone, and Krainov) reproduced the saturation intensities. The atomiclike ionization behavior of molecules indicates that the fragmentation occurs after the ionization. The fragmentation mechanisms after the ionization of some molecular ions are discussed. 相似文献
102.
103.
104.
On the basis of the quantum white noise theory we introduce the notion of creation- and annihilation-derivatives of Fock space
operators and study the differentiability of white noise operators. We define the Hitsuda–Skorohod quantum stochastic integrals
by the adjoint actions of quantum stochastic gradients and show explicit formulas for their creation- and annihilation-derivatives.
As an application, we derive direct formulas for the integrands in the quantum stochastic integral representation of a regular
quantum martingale.
Work supported by the Korea–Japan Basic Scientific Cooperation Program “Noncommutative Stochastic Analysis and Its Applications
to Network Science.” 相似文献
105.
106.
By the use of catalytic amounts of a nickel salt and a 1,3-butadiene, primary and secondary alkyl Grignard reagents undergo cross-coupling with alkyl bromides, iodide, and tosylate carrying a functional group such as amide, ester, and ketone at 0 °C in THF. The present procedure provides a simple, convenient, and practical method for construction of carbon chains in the presence of various functional groups. PhMgBr also gave the corresponding coupling product in a moderate yield. 相似文献
107.
De Lie An Qiang Chen Hong Yan Nobuaki Miura Kenji Monde Junzo Otera 《Tetrahedron letters》2009,50(15):1689-1692
Stereochemical study of cyclophynes, which is otherwise rather difficult to perform, can be achieved by vibrational CD spectroscopy. 相似文献
108.
Takashi Kosone Chikahide Kanadani Toshiaki Saito Takafumi Kitazawa 《Polyhedron》2009,28(9-10):1930-1934
109.
The phenolic-group capacities of five humic substances, such as, the Aldrich humic acid, the humic and fulvic acids extracted from a soil, the humic and fulvic acids extracted from a peat have been precisely determined by the non-aqueous potentiometric titration technique. The titration by KOH in the mixed solvent of DMSO:2-propanol:water = 80:19.3:0.7 at [K+] = 0.02 M enabled to measure the potential change in a wide range of pOH (=−log [OH−]), and thus to determine the capacities of phenolic groups which could not be precisely determined in the aqueous titration. The results of the titration revealed that the mean protonation constants of the phenolic groups were nearly the same for all humic substances and close to that of phenol in the same medium, indicating that each phenolic-group in the humic substances is rather isolated and is not electronically affected by other affecting groups in the humic macromolecule. 相似文献
110.
Nobuaki Seiji Tomoyuki Shuji Yasukazu 《Journal of Photochemistry and Photobiology, C: Photochemistry Reviews》2000,1(2)
New research fields have opened up that are related to the interactions between molecules and high-intensity optical fields where the laser intensity ranges from 1012–1017 W cm−2. A broad outline of this area will be described from the perspective of products and new techniques for beam generation. Studies of large molecules have begun and some examples are introduced herein. Parent ions with little fragmentation are found to form in the intensity region below 1016 W cm−2. The formation of intact ions can be used in femtosecond laser mass spectrometry. In the intensity region above 1016 W cm−2, electrons are stripped from the molecules by optical field ionization and the highly charged ions can undergo a Coulomb explosion. Coulomb explosions of benzene and C60 have been demonstrated, and the mechanism can be analyzed by means of molecular dynamics simulations. A high intensity femtosecond laser beam can be converted to radiation sources of coherent VUV light, X-rays etc. and some possibilities for new chemical applications will be discussed. 相似文献