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  • 1
    Electronic Resource
    Electronic Resource
    A new scheme to calculate dipole-allowed singlets in conjugated polymers (1998)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 109 (1998), S. 2562-2564 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Properly combined with the Lanczos iteration algorithm, the density matrix renormalization group enables us to directly calculate the dipole-allowed singlet states and the transition moment elements between these states and the ground state for longer chains. Our new scheme does not resort to reflection symmetry and electron-hole symmetry, nor to the construction of different superblocks for the ground state and these singlets separately. As an example, we calculate the ground state and first-excited state in the extended Hubbard model. Our calculations show that for a large U, the transition matrix elements decrease with the chain length; for V around U/2, the transition matrix elements can increase with the chain length, which is consistent with recent experimental results. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.476829
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  • 2
    Electronic Resource
    Electronic Resource
    Photoinduced Charge Transfer in Excited C60 (1995)
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 99 (1995), S. 12301-12304 
    Details
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/j100032a038
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  • 3
    Electronic Resource
    Electronic Resource
    Normal mode analysis for a comparative study of relaxation processes of charge transfer and photoexcitation in C60 (1997)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 106 (1997), S. 6398-6403 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: In this article we employ a normal mode analysis to the relaxation processes of charge transfer and photoexcitation in C60. It is found that only a few Hg modes, the so-called dominant modes, play a critical role in the relaxation, which may imply that only a few Hg modes can have a strong electron–phonon coupling constant. This is consistent with recent experimental results, although previous calculations reported that almost all the Hg modes have roughly the same coupling constant. Those dominant modes control mainly the early and the later behaviors and determine the relaxation times of the processes. The difference between the relaxation times of charge transfer and photoexcitation can also be understood from the dominant modes. We discover that the eigenvectors of the dominant modes are very unique, i.e., if the bond lengths are altered along the eigenvectors, one can observe a change in the lattice by a typical laminar distortion structure. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.473630
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  • 4
    Electronic Resource
    Electronic Resource
    Optical origin of efficient and selective trans↔cis isomerization in photoexcited polyenes: An ab initio calculation (1999)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 110 (1999), S. 9765-9768 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: An ab initio calculation is carried out to investigate the optical origin of highly-efficient and selective trans↔cis isomerizations in a short polyene. It is found that the highly-efficient isomerization is closely related to the highly-selective optical transitions. These dipole-allowed transitions occur selectively at two configurations with the dihedral angles θ11,12=60° and 120°, where the system can be excited or de-excited and is also able to undergo cis or trans isomerization effectively. For many configurations which are not favorable to the isomerization, the transition matrix elements are basically zero. This rules out many unfavorable transitions at these configurations, which is why photoinduced isomerization is so efficient. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.478942
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  • 5
    Electronic Resource
    Electronic Resource
    Femtosecond spin dynamics in the time domain (1999)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 85 (1999), S. 5657-5659 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Recently magnetization dynamics on the time scale of 100 fs has been observed. In this article, we explain this ultrafast spin dynamics by a microscopic many-body theory. Our theory yields a speed limit of the order of 10 fs for the spin dynamics in Ni. The fundamental mechanism is the dephasing of the initial excited states. We investigate the dephasing effects in detail as a function of the number of electronic states and K points. We also calculate the density of states as a crosscheck of our theory, where the typical satellite structure of nickel is present. Moreover, the magnetic moment of the monolayer is found to be 0.88μB, which is also consistent with the experimental results. Finally, based on our Hamiltonian, we briefly discuss the origin of ferromagnetism in our model. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.369831
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  • 6
    Electronic Resource
    Electronic Resource
    MODE I AND MIXED MODE I/II FATIGUE CRACKING IN Ni3Al(CrB) SINGLE CRYSTALS (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Fatigue & fracture of engineering materials & structures 20 (1997), S. 0 
    Details
    ISSN: 1460-2695
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract— Nominal mode I and mixed mode I/II fatigue tests were carried out using the intermetallic compound Ni3Al(CrB) in the form of single crystal specimens. The effects of crystal orientation and load mode on fatigue crack initiation and growth were studied. The fracture surfaces of the single crystals were characterized by a cleavage-like appearance and cracking occurred either on a single {111} plane or on multiple {111} planes irrespective of whether mode I or mixed mode I/II loadings were applied. It was found that the crack initiation and growth behaviour are dependent on both crystal orientation and applied loading mode. The cracking behaviour predicted by three mixed mode fracture criteria (MTS, SED and G criteria) in polycrystalline materials under mixed mode loading can be understood from the present results on single crystals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1460-2695.1997.tb01532.x
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  • 7
    Electronic Resource
    Electronic Resource
    Charge Transfer and Electron Pairing in Fullerenes (1999)
    Springer
    Journal of cluster science 10 (1999), S. 155-167 
    Details
    ISSN: 1572-8862
    Keywords: Fullerenes ; electron pairing ; charge transfer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Electron transfer is a common characteristic in fullerene complexes and brings about an optoelectronic effect in a polymer-C60 composite and superconductivity in alkali-metal doped C60. This paper reports that the concept of self-trapping of the transferred electron in C60 can explain the main features of photoinduced electron transfer in a polymer-CC60 composite and electron pairing in alkali-metal doped C60.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1022612903543
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  • 8
    Electronic Resource
    Electronic Resource
    Crystallographic cracking behaviour in intermetallic compound Ni3Al(CrB) single crystal under cyclic compression (1997)
    Springer
    Journal of materials science 16 (1997), S. 953-957 
    Details
    ISSN: 1573-4811
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Abstracts are not published in this journal
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018517011632
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  • 9
    Electronic Resource
    Electronic Resource
    Deformation and fracture behaviour in Ni3Al alloy single crystals (1997)
    Springer
    Journal of materials science 17 (1997), S. 61-64 
    Details
    ISSN: 1573-4811
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006549809526
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  • 10
    Electronic Resource
    Electronic Resource
    Localization-delocalization transition in one-dimensional system with long-range correlated diagonal disorder (2002)
    Springer
    The European physical journal 29 (2002), S. 491-495 
    Details
    ISSN: 1434-6036
    Keywords: PACS. 73.20.Jc Delocalization processes – 72.15.Rn Localization effects – 05.40.-a Fluctuation phenomena, random processes, noise, and Brownian motion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract: We show that the electronic states in a one-dimensional (1D) Anderson model of diagonal disorder with long-range correlation proposed by de Moura and Lyra exhibit localization-delocalization phase transition in varying the energy of electrons. Using transfer matrix method, we calculate the average resistivity and investigate how it changes with the size of the system N. For given value of α (〉 2) we find critical energies Ec1 and Ec2 such that the resistivity decreases with N as a power law ∝ N - γ for electron energies within the range of [E c1, E c2], and exponentially grows with N outside this range. Such behaviors persist in approaching the transition points and the exponent γ is in the range from 0.92 to 0.96. The origin of the delocalization in this 1D model is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjb/e2002-00330-7
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