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691.
Kiyoshi Tanaka Yuji Mochizuki Hidemi Terashima Hiroaki Tokiwa 《Theoretical chemistry accounts》2007,117(3):397-405
We developed a spin adapted full configuration interaction (FCI) method which was expected to be effective for parallel processing.
The graphical symmetric group approach (GSGA) was employed, where a configuration graph was partitioned into several sets
of closed-shell and open-shell graphs. The configuration state functions (CSFs) bearing the same number of closed-shells and
open-shells were assembled in a configuration group. The graphical approach provided a number to identify each CSF in a sequential
order within the group. Combination of this partitioning and an intermediate configuration-driven algorithm in calculating
the so-called σ vectors allowed us to use symbolic coupling constants. Furthermore, this combination made it easy to implement
an efficient algorithm suitable to task-distributed parallel procedure for evaluating σ vectors. A program was written and
some test calculations were carried out with high parallel efficiency. The largest size of FCI used 10 million CSFs (20 million
determinants). 相似文献
692.
Masashi Hamaguchi Naoki Tomida Eiko Mochizuki Takumi Oshima 《Tetrahedron letters》2005,46(8):1259-1262
Reaction of azodicarboxylates with acyloxyketenes arising from dehydrochlorination of acyloxyphenylacetyl chlorides was carried out to give triacylamidine derivatives in good yields. The same triacylamidine derivatives were also obtained in good yields from the reaction with mesoionic 1,3-dioxolium-4-olates generated by Rh2(OAc)4-catalyzed decomposition of phenyldiazoacetic anhydride derivatives. Formation of the same compounds from different starting materials is explained by 1,3-dipolar addition between electron deficient NN bonds and mesoionic 1,3-dioxolium-4-olates, indicating fast equilibrium between acyloxyketenes and mesoionic 1,3-dioxolium-4-olates. 相似文献
693.
694.
The preferential solvation and the coordination characterizing metal ions (Mg2+ and Zn2+) in solution, which control the microscopic environments around the metal ions, were directly observed through the mass spectrometric analysis of clusters isolated from liquid droplets. 相似文献
695.
Nakanishi I Kawashima T Ohkubo K Kanazawa H Inami K Mochizuki M Fukuhara K Okuda H Ozawa T Itoh S Fukuzumi S Ikota N 《Organic & biomolecular chemistry》2005,3(4):626-629
The scavenging reaction of 2,2-diphenyl-1-picrylhydrazyl radical (DPPH.) or galvinoxyl radical (GO.) by a vitamin E model, 2,2,5,7,8-pentamethylchroman-6-ol (1H), was significantly accelerated by the presence of Mg(ClO4)2 in de-aerated methanol (MeOH). Such an acceleration indicates that the radical-scavenging reaction of 1H in MeOH proceeds via an electron transfer from 1H to the radical, followed by a proton transfer, rather than the one-step hydrogen atom transfer which has been observed in acetonitrile (MeCN). A significant negative shift of the one-electron oxidation potential of 1H in MeOH (0.63 V vs. SCE), due to strong solvation as compared to that in MeCN (0.97 V vs. SCE), may result in change of the radical-scavenging mechanisms between protic and aprotic media. 相似文献
696.
Yuji Mochizuki Naoki Nishi Yukio Hirahara Toshikazu Takada 《Theoretical chemistry accounts》1996,93(4):211-233
Summary A direct configuration interaction (CI) scheme using the generalized double symbolism both for the external space and for the internal space is proposed in an integral-driven context. The reason why the double symbolism is used in the present formulation is that the main target is in investigating large molecular systems. The integrals, configuration state functions, and energy expressions are systematically classified in terms of the orbital labels and their mutual relations. Various types of CI wavefunctions can be set up flexibly. The resulting structure of integral processings in the sigma vector construction is complicated. The number of unique loop types for two-electron integrals is 1325. Because the parallel architecture is gaining importance in the recent computational platforms, the parallelism is also addressed. 相似文献
697.
The flexoelectric effect of 4-heptyloxy-4'-cyanobiphenyl (7OCB) monolayers at the air-water interface is studied by Maxwell displacement current (MDC) and optical second harmonic generation measurements. Though MDC was expected to increase during the compression of 7OCB monolayers in L2L2' phase from the MDC theory developed previously, decrease of MDC was detected in these phases. This abnormalous phenomenon is found to be due to the quench of flexoelectric effect by the flow orientation of monolayers. 相似文献
698.
Takeji Takamura-Enya Satoko IshikawaMasataka Mochizuki Keiji Wakabayashi 《Tetrahedron letters》2003,44(32):5969-5973
Synthetic methods for the preparation of 2′-deoxyguanosine-C8 (dG-C8) adducts with several mutagenic and carcinogenic amino- or nitro-arenes were developed using the palladium-mediated cross-coupling reaction of protected 8-amino-dG with bromoarenes in around 80% yields, followed by conventional deprotection procedures. This approach can be applied to preparation of a variety of authentic dG-C8 adducts with amino or nitro-arenes. 相似文献
699.
Essam Mohamed Sharshira Haruki Iwanami Mutsuo Okamura Eietsu Hasegawa Takaaki Horaguchi 《Journal of heterocyclic chemistry》1996,33(1):17-25
Photocyclization reactions were carried out on 8-alkoxy-1,2,3,4-tetrahydro-1-naphthalenones (six-membered ring ketones) 4a-g and 4-alkoxy-6,7,8,9-tetrahydro-5H-benzocyclohepten-5-ones (seven-membered ring ketones) 5a -e in acetonitrile. Irradiation of 4a-f gave rearranged naphthyl alcohols 8a-f as major products. In the case of 4g , 2a,3,4,5-tetrahydronaphtho[1,8-bc]furan-2a-ol 6g was obtained. In contrast, irradiation of 5a-e afforded 2,2a,3,4,5,6-hexahydrocyclohepta[cd]benzofuran-2a-ols 9a-e in good yields. The difference in reactivities between 4a-g and 5a-e is attributed to the conformation of six- and seven-membered rings. Conformational and substituent effects in cyclization step of 1,5-biradicals are discussed along with reaction pathways. 相似文献
700.
A mild and efficient procedure for alpha-bromination of ketones using N-bromosuccinimide catalysed by ammonium acetate 总被引:1,自引:0,他引:1
Tanemura K Suzuki T Nishida Y Satsumabayashi K Horaguchi T 《Chemical communications (Cambridge, England)》2004,(4):470-471
Cyclic ketones reacted with N-bromosuccinimide (NBS) catalysed by NH(4)OAc in Et(2)O at 25 degrees C to give the corresponding alpha-brominated ketones in good yields, while acyclic ketones were efficiently brominated in CCl(4) at 80 degrees C. 相似文献