نتایج جستجو برای: chemical bond

تعداد نتایج: 440732  

2009
An-yin Chen Zhang-Gao Le Gang Liu Shou-Zhi Pu Cong-Bin Fan

The title compound, C(29)H(19)F(6)NOS(2), is a new unsymmetrical photochromic diarylethene derivative with different meta-phenyl substituents. The distance between the two reactive (i.e. can be irradiated to form a new chemical bond) C atoms is 3.501 (4) Å; the dihedral angles between the mean plane of the main central cyclo-pentene ring and the thio-phene rings are 47.7 (5) and 45.1 (2)°, and ...

2000
D. Xue K. Betzler H. Hesse D. Lammers P. Dederichs

We have studied the effect of different chemical bonding structures of boron atoms on the second-order nonlinear optical behavior of borate crystals from the chemical bond viewpoint. Several typical borate crystals, including LiB3O5, b-BaB2O4, BiB3O6, NdAl3(BO3)4, Ca4LnO(BO3)3, K[B5O6(OH)4]·2H2O, Eu2B5O9Cl and Ca2B5O9Br, with different chemical bonding structures of boron atoms are investigated...

Journal: :The Journal of chemical physics 2012
Doo-Sik Ahn Jeongmook Lee Young Choon Park Yoon Sup Lee Sang Kyu Kim

Predissociation dynamics of methylamines (CH(3)NH(2) and CH(3)ND(2)) on the first electronically excited states are studied using the slow-electron velocity imaging method to unravel the multi-dimensional nature of the N-H(D) chemical bond dissociation reaction which occurs via tunnelling. The nearly free internal rotation around the C-N bond axis is found to be strongly coupled to the reaction...

2007
Hinne Hettema

Weisberg’s 2007 recent paper on the chemical bond makes the claim that the chemical notion of the covalent bond is in trouble. This note casts doubts on that claim.

Journal: :Nature communications 2013
Joost van der Lit Mark P Boneschanscher Daniël Vanmaekelbergh Mari Ijäs Andreas Uppstu Mikko Ervasti Ari Harju Peter Liljeroth Ingmar Swart

Graphene nanostructures, where quantum confinement opens an energy gap in the band structure, hold promise for future electronic devices. To realize the full potential of these materials, atomic-scale control over the contacts to graphene and the graphene nanostructure forming the active part of the device is required. The contacts should have a high transmission and yet not modify the electron...

Journal: :Physical review letters 2007
V M Karpan G Giovannetti P A Khomyakov M Talanana A A Starikov M Zwierzycki J van den Brink G Brocks P J Kelly

Based upon the observations (i) that their in-plane lattice constants match almost perfectly and (ii) that their electronic structures overlap in reciprocal space for one spin direction only, we predict perfect spin filtering for interfaces between graphite and (111) fcc or (0001) hcp Ni or Co. The spin filtering is quite insensitive to roughness and disorder. The formation of a chemical bond b...

Journal: :Physical chemistry chemical physics : PCCP 2011
Paul S Julienne Thomas M Hanna Zbigniew Idziaszek

Universal collision rate constants are calculated for ultracold collisions of two like bosonic or fermionic heteronuclear alkali-metal dimers involving the species Li, Na, K, Rb, or Cs. Universal collisions are those for which the short range probability of a reactive or quenching collision is unity such that a collision removes a pair of molecules from the sample. In this case, the collision r...

2015
Wujie Qiu Lihua Wu Xuezhi Ke Jihui Yang Wenqing Zhang

Searching and designing materials with extremely low lattice thermal conductivity (LTC) has attracted considerable attention in material sciences. Here we systematically demonstrate the diverse lattice dynamics of the ternary Cu-Sb-Se compounds due to the different chemical-bond environments. For Cu3SbSe4 and CuSbSe2, the chemical bond strength is nearly equally distributed in crystalline bulk,...

Journal: :Physical chemistry chemical physics : PCCP 2013
Ping Wu Pan Du Hui Zhang Chenxin Cai

We report a density functional theory (DFT) study of microscopic detailed effects of the bonding configuration of nitrogen-doped graphene (N-graphene) within the carbon lattice (including pyridinic, pyrrolic, and graphitic N) on the reactivity and mechanistic processes of H2O2 reduction reaction. We simulated the adsorption process of H2O2, analyzed the mechanistic processes, and calculated the...

Journal: :Physical review letters 2005
Boris Ravaine Sergey G Porsev Andrei Derevianko

Heavy polar molecules offer a great sensitivity to the electron electric dipole moment (EDM). To guide emerging searches for EDMs with molecular ions, we estimate the EDM-induced energy corrections for hydrogen halide ions HBr(+) and HI(+) in their respective ground X (2)Pi(3/2) states. We find that the energy corrections due to EDM for the two ions differ by an unexpectedly large factor of 15....

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