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APPLIED BIOPHYSICS

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Long-range electron transfer and electronic transport through macromolecules

Natalya Zimbovskaya and Godfrey Gumbs

Appl. Phys. Lett. 81, 1518 (2002); http://dx.doi.org/10.1063/1.1502004 (3 pages) | Cited 8 times

Online Publication Date: 9 August 2002

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A theory of electrical transport through molecular wires is used to estimate the electronic factor in the intramolecular electron transfer in porphyrin-nitrobenzene supermolecules, and to analyze its structure. The chosen molecules have complex donor and acceptor configurations, and relatively simple structure of the bridge, which enables us to concentrate our studies on the donor/acceptor coupling to the bridge. We present analytical and numerical results concerning the effect of donor/acceptor coupling to the bridge on the electron transfer process in molecules with complex donor/acceptor subsystems. © 2002 American Institute of Physics.

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72.20.Ee	Mobility edges; hopping transport
72.80.Le	Polymers; organic compounds (including organic semiconductors)
73.61.Ph	Polymers; organic compounds
85.65.+h	Molecular electronic devices
71.15.Ap	Basis sets (LCAO, plane-wave, APW, etc.) and related methodology (scattering methods, ASA, linearized methods, etc.)

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Effect on laser-ablation algorithms of reflection losses and nonnormal incidence on the anterior cornea

J. R. Jiménez, R. G. Anera, L. Jiménez del Barco, and E. Hita

Appl. Phys. Lett. 81, 1521 (2002); http://dx.doi.org/10.1063/1.1502192 (3 pages) | Cited 33 times

Online Publication Date: 9 August 2002

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In this paper, we provide an analytic expression for an adjustment factor in ablation algorithms for photorefractive laser surgery which take into account reflection losses and the nonnormal incidence on the cornea. We evaluate the influence of this factor on certain ocular parameters, calculating alterations in the radius of anterior cornea and corneal asphericity when we use the algorithm given by Munnerlyn’s paraxial formula. Our data indicate that this adjustment factor should be considered in the ablation algorithms that are currently being proposed in customized corneal ablation and that need great accuracy for the correction of eye aberrations. © 2002 American Institute of Physics.

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42.62.Be	Biological and medical applications
42.66.-p	Physiological optics

INTERDISCIPLINARY AND GENERAL PHYSICS

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Modulation of x-ray line intensity emitted by a periodic structure under electron excitation

P. Jonnard, J.-M. Ândré, C. Bonnelle, F. Bridou, and B. Pardo

Appl. Phys. Lett. 81, 1524 (2002); http://dx.doi.org/10.1063/1.1502189 (3 pages) | Cited 2 times

Online Publication Date: 9 August 2002

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We report on the intensity modulation of a characteristic x-ray line emitted by a periodic structure, as a function of the observation angle. This intensity variation takes place around the Bragg direction corresponding to the diffraction of the x-ray line by the emitting structure. An enhancement of the emitted radiation is observed and interpreted on the basis of the reciprocity theorem. The enhancement remains unchanged by varying the number of emitting periods. Following Yariv and Yeh [J. Opt. Soc. Am. 67, 438 (1977)], a possible application as x-ray resonator to achieve a distributed feedback soft x-ray laser is envisaged. © 2002 American Institute of Physics.

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42.60.Fc	Modulation, tuning, and mode locking
78.70.En	X-ray emission spectra and fluorescence
78.66.Db	Elemental semiconductors and insulators
42.79.Wc	Optical coatings

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Nanotomography based on hard x-ray microscopy with refractive lenses

C. G. Schroer, J. Meyer, M. Kuhlmann, B. Benner, T. F. Günzler, B. Lengeler, C. Rau, T. Weitkamp, A. Snigirev, and I. Snigireva

Appl. Phys. Lett. 81, 1527 (2002); http://dx.doi.org/10.1063/1.1501451 (3 pages) | Cited 24 times

Online Publication Date: 9 August 2002

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Based on parabolic refractive x-ray lenses we have built a hard x-ray microscope that allows one to image the interior of opaque samples with submicrometer resolution. We have combined magnified imaging with tomography to obtain the three-dimensional structure of the sample at a resolution well below 1 μm. Using an aluminum lens to record a magnified tomogram of a test sample (microprocessor), a resolution of slightly above 400 nm was found for the three-dimensional reconstruction. Lenses made of beryllium are expected to improve this resolution to well below 100 nm. The resulting challenges concerning instrumentation and numerical methods are discussed. © 2002 American Institute of Physics.

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41.50.+h	X-ray beams and x-ray optics
07.85.Tt	X-ray microscopes
42.79.Bh	Lenses, prisms and mirrors

COMMENTS

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Comment on “Forward current propagation beyond the virtual cathode formed by a high injection current” [Appl. Phys. Lett, 79, 913 (2001)]

Alexander E. Dubinov and Irina A. Efimova

Appl. Phys. Lett. 81, 1530 (2002); http://dx.doi.org/10.1063/1.1495884 (2 pages) | Cited 4 times

Online Publication Date: 9 August 2002

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Abstract Unavailable

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84.40.Fe	Microwave tubes (e.g., klystrons, magnetrons, traveling-wave, backward-wave tubes, etc.)
85.30.Fg	Bulk semiconductor and conductivity oscillation devices (including Hall effect devices, space-charge-limited devices, and Gunn effect devices)

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Response to “Comment on ‘Forward current propagation beyond the virtual cathode formed by a high injection current’ ” [Appl. Phys. Lett. 81, 1530 (2002)]

Han S. Uhm, Eun H. Choi, and Myung C. Choi

Appl. Phys. Lett. 81, 1532 (2002); http://dx.doi.org/10.1063/1.1495885 (2 pages) | Cited 1 time

Online Publication Date: 9 August 2002

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Abstract Unavailable

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84.40.Fe	Microwave tubes (e.g., klystrons, magnetrons, traveling-wave, backward-wave tubes, etc.)
85.30.De	Semiconductor-device characterization, design, and modeling
85.30.Fg	Bulk semiconductor and conductivity oscillation devices (including Hall effect devices, space-charge-limited devices, and Gunn effect devices)