Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Theory for the laser-induced femtosecond phase transition of silicon and GaAs (1995)
    Springer
    Applied physics 60 (1995), S. 191-196 
    Details
    ISSN: 1432-0630
    Keywords: PACS: 61.80.Ba; 63.20. ; e; 78.47.+p
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract.  We analyze the femtosecond instability of the diamond lattice of silicon and GaAs, which is induced by a dense electron–hole plasma after excitation by a very intense laser pulse. We obtain that the electron–hole plasma causes an instability of both transverse acoustic and longitudinal optical phonons. So, within less than 200 fs, the atoms are displaced more than 1 A˚ from their equilibrium position. The gap between the conduction and the valence band then vanishes and the symmetries of the diamond structure are destroyed, which has important effects on the optical reflectivity and second-harmonic generation. After that, the crystal melts very rapidly because of the high kinetic energy of the atoms. Note that this is in good agreement with recent experiments done on Si and GaAs using a pump laser to excite a dense electron–hole plasma and a probe laser to observe the resulting changes in the atomic and electronic str ucture.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003390050089
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Electron attachment to oxygen clusters studied with high energy resolution (1999)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 111 (1999), S. 3548-3558 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Highly monochromatized electrons (with energy distributions of less than 30 meV FWHM) are used in a crossed beam experiments to investigate electron attachment to oxygen clusters (O2)n at electron energies from approximately zero eV up to several eV. At energies close to zero the attachment cross section for the reaction (O2)n+e→(O2)m− (for m=1, 2, and 3) rises strongly with decreasing electron energy compatible with s-wave electron capture to (O2)n. Peaks in the oxygen attachment cross sections present at higher energies ((approximate)80 meV, 193 meV, 302 meV) can be ascribed to vibrational levels of the anion populated by attachment of an electron to a single oxygen molecule within the target cluster via a direct Franck–Condon transition from the ground vibrational state v=0 to a vibrational excited state v′=7,8,9,... of the anion produced. The vibrational structures observed here for the first time can be quantitatively accounted for by model calculations using a microscopic model to examine the attachment of an electron to an oxygen molecule inside a cluster. This involves (i) molecular dynamics simulations to calculate the structure of neutral clusters prior to the attachment process and (ii) calculation of the solvation energy of an oxygen anion in the cluster from the electrostatic polarization of the molecules of the cluster. The occurrence of this polarization energy at the surface of larger clusters explains the appearance of an s-wave capturing cross section at 0 eV and the slightly smaller spacings (compared to the monomer case) between the peaks at finite energy, as observed experimentally. The relative transition probabilities from the ground state of the neutral oxygen molecule to the different vibrational levels of the anion are obtained by calculating the corresponding Franck–Condon factors thereby resulting in a reasonable theoretical fit to the observed yields of negatively charged oxygen molecules and clusters. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.479637
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Theory for the laser-induced instability of the diamond structure of Si, Ge and C
    Amsterdam : Elsevier
    Progress in Surface Science 35 (1990), S. 161-164 
    Details
    ISSN: 0079-6816
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0079-6816(90)90034-H
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Electron affinity of clusters and liquids of polar molecules: Theory of many-body polarization interactions (1994)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 101 (1994), S. 6024-6031 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: We examine the attractive interaction between an excess electron and the dipole moments of polar molecules forming a cluster or a liquid. This interaction determines the size dependence of the electron affinity of these clusters. We use the polarizable electropole model for the molecules and include interactions between the permanent and induced dipole moments. Thus, we obtain that the interaction between the excess electron and the molecules is strongly decreased by the induced polarization of the bound electrons, which is opposed to the permanent dipole moments and makes a dielectric screening. Note that previous calculations of the electron affinity of clusters of polar molecules resulted in much larger vertical detachment energies of the excess electron than observed in the experiment. This error is due to the use of an unphysical pair-potential approximation, which neglects the interaction between the permanent dipole moments and induced dipole moments. Thus the attractive interaction between the excess electron and the molecules and the resulting electronic binding energies have been overestimated. The results of our microscopic theory are identical with macroscopic continuum models and agree very well with experimental results. This theory also might be important for the study of solvent effects on oxidation–reduction reactions and on photosynthesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.467317
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Core level binding energy shifts and polarization screening: A combined experimental and theoretical study of argon clusters (1996)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 104 (1996), S. 1846-1854 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Photoelectron spectra of the argon 2p core level for free argon clusters of up to 4000 atoms are compared to detailed calculations. The comparison shows that the size-dependent shifts of the core level binding energy can be explained in a pure polarization-screening model. Important differences arise between the shifts for the bulk (interior) and the surface atoms. The agreement between experiment and theory allows the extrapolation of the cluster data to the "infinite'' solid. In this way we obtain the shifts of the core level binding energy between the free atom, the surface atom and the bulk of argon. The relation between these shifts and those of the first ionization potential is discussed. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.470981
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Superconductivity and nonuniform magnetic order in itinerant ferromagnets
    Amsterdam : Elsevier
    Solid State Communications 64 (1987), S. 1359-1362 
    Details
    ISSN: 0038-1098
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0038-1098(87)90392-9
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Theory for the laser-induced femtosecond phase transition of silicon and GaAS (1995)
    Springer
    Applied physics 60 (1995), S. 191-196 
    Details
    ISSN: 1432-0630
    Keywords: 61.80.Ba ; 63.20.-e ; 78.47.+p
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract We analyze he femtosecond instability of the chamond lattice of silicon and GaAs, which is induced by a dense electron-hole plasma after excitation by a very imense laser pulse. We obtain that the electron-hole plasma causes an instability of both transverse acoustic and longitudinal optical phonons. So, within less than 200fs, the atoms are displaced more than 1 Å from their equilibrium position. The gap between the conduction and the valence band then vanishes and the symmetries of the diamond structure are destroyed, which has important effects on the optical reflectivity and second-harmonic generation. After that, the crystal melts very rapidly because of the high kinetic energy of the atoms. Note that mis is in good agreement with recent experiments done on Shand GaAs using a pump laser to excite a dense electron hole plasma and a probe laser to observe the resulting changes in the atomic and electronic structure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01538245
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Calculation of the size dependence of the ionization energy and autoionization energy of Hg-clusters (1989)
    Springer
    The European physical journal 12 (1989), S. 365-367 
    Details
    ISSN: 1434-6079
    Keywords: 36.40.+d
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract To study the transition from van der Waals to metallic bonding we calculate the size dependence of the ionization energy and 5d→6p autoionization energy of Hg n -clusters using a parametrized LCAO model. Our results are in good qualitative agreement with experiment. Comparison with experimental results suggests that electron correlations play an important role for the transition from localized (van der Waals-like) to delocalized (covalent or metallic) electronic states occuring in Hg n atn≃13–19.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01426973
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Theory for excess electrons in clusters of rare gas atoms (1991)
    Springer
    The European physical journal 20 (1991), S. 53-55 
    Details
    ISSN: 1434-6079
    Keywords: 36.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract An exact theory for excess electrons in clusters of rare gas atoms is limited to small sizes,n 〈 20, because of many body polarization interactions which make it necessary to solve a large system of linear equations. We present a simple dielectric screening approximation, which avoids this difficulty and which is in very good agreement with the exact calculation. This approximation can be used to examine the excitation energies of excess electrons and exciton energies in large clusters. A new atomic structure is proposed for a cluster of 12 Xe atoms, resulting in an increased binding energy for the excess electron, which is larger than the electron affinity of a cluster of 13 atoms. This might explain the relatively large abundance of Xe 12 − observed in the experiment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01543936
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Theory of nonlinear optical properties of small metallic spheres (1993)
    Springer
    The European physical journal 28 (1993), S. 169-175 
    Details
    ISSN: 1434-6079
    Keywords: 42.65.K ; 36.40 ; 73.35
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We calculate the nonlinear optical properties of small metallic spheres using electromagnetic theory and assuming that the local response of the conduction electrons is the same as for a plane surface. Electromagnetic Mie-resonances cause a strong increase of the second and higher harmonics in the reflected light. Detailed results are given for the second and third harmonic generation, its dependence on the frequency and polarization of the incident light, and on the cluster size. An enhancement of the second harmonic generation by a factor of about 5000 is obtained for small spherical metallic clusters. This is in good agreement with experiments on artificially roughened metal surfaces.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01436985
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...