@article{HoheiselVollmerTraeger1993, author = {Hoheisel, W. and Vollmer, Michael and Tr{\"a}ger, F.}, title = {Desorption of metal atoms with laser light: Mechanistic studies}, series = {In: Physical Review / B 48 1993) 23, 17463-17476}, journal = {In: Physical Review / B 48 1993) 23, 17463-17476}, doi = {10.1103/PhysRevB.48.17463}, year = {1993}, abstract = {Results on laser-induced desorption of metal atoms from small metal particles are presented. Experiments have been performed on sodium, potassium, and silver particles supported on a LiF(100) single-crystal surface under ultrahigh vacuum conditions. Measurements include the determination of the desorption rate as a function of laser wavelength, laser intensity, average particle size, and substrate temperature, the determination of the kinetic energy of the desorbed atoms, the investigation of the optical spectra of the supported metal particles, and the study of the influence of adsorbate molecules on the desorption rate. Furthermore, theoretical extinction and absorption spectra of the metal particles have been calculated with the classical electrodynamical Mie theory as a function of average particle size and excitation wavelength. Also, the radial electric field at the particle surface was computed. The results of the experiments and theoretical calculations are combined to give a consistent picture of the mechanism of metal-atom desorption by electronic excitation with laser light. A realistic surface potential from which the atoms escape and nonlocal optical effects are taken into account. The latter introduce additional absorption channels by the formation of electron-hole pairs in the surface layer of the particle which relax into antibonding states before desorption occurs. Finally, the mechanism is discussed in the light of similar phenomena observed for thin metal films. Possibilities for future work are outlined. © 1993 The American Physical Society}, language = {en} } @article{GoetzHoheiselTraegeretal.1993, author = {G{\"o}tz, T. and Hoheisel, W. and Tr{\"a}ger, F. and Vollmer, Michael}, title = {Interplay between collective and single electron excitations in large metal clusters}, series = {In: Zeitschrift f{\"u}r Physik / D 26 (1993), 267-269}, journal = {In: Zeitschrift f{\"u}r Physik / D 26 (1993), 267-269}, year = {1993}, language = {en} } @incollection{VollmerKreibig1992, author = {Vollmer, Michael and Kreibig, U.}, title = {Collective excitations of large metal clusters}, series = {In: Nuclear physics concepts in the study of atomic cluster physics : proceedings of the 88th W.-E.-Heraeus-Seminar, held at Bad Honnef, FRG, 26 - 29 November 1991 / R. Schmidt ... (ed.). - Berlin [u.a.] : Springer, 1992. - (Lecture notes in physics ; Vol. 404). - ISBN 3-540-55625-7 ; 0-387-55625-7. - S. 266-276}, booktitle = {In: Nuclear physics concepts in the study of atomic cluster physics : proceedings of the 88th W.-E.-Heraeus-Seminar, held at Bad Honnef, FRG, 26 - 29 November 1991 / R. Schmidt ... (ed.). - Berlin [u.a.] : Springer, 1992. - (Lecture notes in physics ; Vol. 404). - ISBN 3-540-55625-7 ; 0-387-55625-7. - S. 266-276}, doi = {10.1007/3-540-55625-7_30}, pages = {266 -- 276}, year = {1992}, abstract = {Studies of the evolution of the optical properties of metal clusters as a function of size have gained considerable attention in the last few years. One theoretical approach starts from large metal clusters, which can be described by classical electrodynamics, provided the dielectric functions of the clusters are known. the resulting resonant features in the absorption spectra are commonly called surface plasmons and are collective excitations of the electron system.The present paper discusses the electrodynamic (Mie) theory for large clusters of different metals, also considering the range of validity of this approach towards smaller cluster sizes. More details can be found in an extended review on this topic which is to be published soon [1].}, language = {en} } @inproceedings{MoellmannPinnoVollmer2009, author = {M{\"o}llmann, Klaus-Peter and Pinno, Frank and Vollmer, Michael}, title = {Microscopic and high-speed thermal imaging: a powerful tool in physics R\&D}, series = {In: InfraMation proceedings Vol.10 (2009), 303-317}, booktitle = {In: InfraMation proceedings Vol.10 (2009), 303-317}, pages = {303 -- 317}, year = {2009}, language = {en} } @inproceedings{VollmerMoellmannPinno2008, author = {Vollmer, Michael and M{\"o}llmann, Klaus-Peter and Pinno, Frank}, title = {Cheese cubes, light bulbs, soft drinks: An unusual approach to study convection, radiation and size dependent heating and cooling}, series = {In: InfraMation proceedings Vol. 9 (2008), p. 477-492}, booktitle = {In: InfraMation proceedings Vol. 9 (2008), p. 477-492}, pages = {477 -- 492}, year = {2008}, language = {en} } @inproceedings{MoellmannPinnoVollmer2008, author = {M{\"o}llmann, Klaus-Peter and Pinno, Frank and Vollmer, Michael}, title = {Night sky radiant cooling - influence on outdoor thermal imaging analysis}, series = {In: InfraMation proceedings Vol. 9 (2008), 279-295}, booktitle = {In: InfraMation proceedings Vol. 9 (2008), 279-295}, pages = {279 -- 295}, year = {2008}, language = {en} } @inproceedings{PinnoMoellmannVollmer2008, author = {Pinno, Frank and M{\"o}llmann, Klaus-Peter and Vollmer, Michael}, title = {Thermography of window panes - problems, possibilities and troubleshooting}, series = {In: InfraMation proceedings Vol. 9 (2008), 355-362}, booktitle = {In: InfraMation proceedings Vol. 9 (2008), 355-362}, pages = {355 -- 362}, year = {2008}, language = {en} } @article{VollmerGedzelman2008, author = {Vollmer, Michael and Gedzelman, Stanley David}, title = {Simulating irradiance during lunar eclipses: the spherically Symmetric case}, series = {In: Applied Optics 47 (2008) 34, H52-61}, journal = {In: Applied Optics 47 (2008) 34, H52-61}, doi = {http://dx.doi.org/10.1364/AO.47.000H52}, pages = {H52 -- H61}, year = {2008}, abstract = {Irradiance during total lunar eclipses is simulated using a pinhole model. The Moon is illuminated by direct sunlight that is refracted into the Earth's shadow as it passes through the atmosphere at the terminator but is depleted by scattering by molecules, extinction by aerosol particles, absorption by ozone, and obstruction by clouds and elevated land. On a spherical, sea-level Earth, and a cloudless, molecular atmosphere with no ozone, the eclipsed Moon appears red and calculated irradiance at the center of the umbra is reduced by a factor of about 2400 from direct moonlight. Selective absorption mainly of light around 600 nm by stratospheric ozone turns the periphery of the umbra pale blue. Typical distributions of aerosol particles, ozone, mountains, and clouds around the terminator reduce irradiance by an additional factor of the order of 100. © 2008 Optical Society of America}, language = {en} } @article{GedzelmanVollmer2008, author = {Gedzelman, Stanley David and Vollmer, Michael}, title = {Simulating irradiance and color during lunar eclipses using satellite data}, series = {In: Applied Optics 47 (2008) 34, pp. H149-H156}, journal = {In: Applied Optics 47 (2008) 34, pp. H149-H156}, doi = {http://dx.doi.org/10.1364/AO.47.00H149}, pages = {H149 -- H156}, year = {2008}, abstract = {Irradiance and color during the total lunar eclipses of 2007 and 2008 are simulated using a ray tracing model that includes refraction, scattering by molecules, and observed or climatological distributions of aerosols, ozone, clouds, and topography around the terminator. Central portions of the umbra appear deep red for almost all eclipses due to preferential removal of short wavelengths in the spectrum of sunlight by scattering in the lower troposphere. The fringe of the umbra appears turquoise or blue due to selective removal of wavelengths around 600 nm by the Chappuis absorption bands of ozone in the stratosphere. Asymmetric distributions of clouds and aerosols, particularly for the 2008 eclipse, produce minimum calculated irradiance up to 17  arc min from the umbra center, while high ozone content over the arctic makes the northern edge of the umbra deepest blue. © 2008 Optical Society of America}, language = {en} } @article{HernitschekSchmidtVollmer2008, author = {Hernitschek, Nina and Schmidt, Elmar and Vollmer, Michael}, title = {Lunar eclipse photometry: absolute luminance measurements and modeling}, series = {In: Applied optics 47 (2008) 34, pp. H62-H71}, journal = {In: Applied optics 47 (2008) 34, pp. H62-H71}, doi = {10.1364/AO.47.000H62}, pages = {H62 -- H71}, year = {2008}, abstract = {The Moon's time-dependent luminance was determined during the 9 February 1990 and 3 March 2007 total lunar eclipses by using calibrated, industry standard photometers. After the results were corrected to unit air mass and to standard distances for both Moon and Sun, an absolute calibration was accomplished by using the Sun's known luminance and a pre-eclipse lunar albedo of approximately 13.5\%. The measured minimum level of brightness in the total phase of both eclipses was relatively high, namely -3.32 mvis and -1.7 mvis , which hints at the absence of pronounced stratospheric aerosol. The light curves were modeled in such a way as to let the Moon move through an artificial Earth shadow composed of a multitude of disk and ring zones, containing a relative luminance data set from an atmospheric radiative transfer calculation. © 2008 Optical Society of America}, language = {en} } @inproceedings{MoellmannPinnoVollmer2007, author = {M{\"o}llmann, Klaus-Peter and Pinno, Frank and Vollmer, Michael}, title = {Influence of wind effects on thermal imaging results - Is the wind chill effect relevant ?}, series = {In: InfraMation proceedings Vol. 8 (2007), 21-31}, booktitle = {In: InfraMation proceedings Vol. 8 (2007), 21-31}, pages = {21 -- 31}, year = {2007}, language = {en} } @article{GedzelmanVollmer2008, author = {Gedzelman, Stanley David and Vollmer, Michael}, title = {Atmospheric Optical Phenomena and Radiative Transfer}, series = {In: Bulletin of the American Meteorological Society. 89 (2008) 4, 471-485}, journal = {In: Bulletin of the American Meteorological Society. 89 (2008) 4, 471-485}, doi = {10.1175/BAMS-89-4-471}, pages = {471 -- 485}, year = {2008}, abstract = {We present simple radiative transfer models for the radiance and color of atmospheric optical phenomena. Skylight, halos, and rainbows are treated as singly scattered sunlight that is depleted by scattering as it passes through a plane-parallel atmosphere and a vertical rain shaft or a geometrically thin cloud layer. Skylight in a molecular atmosphere grades from deep blue at the zenith to pale blue near the horizon whenever the solar zenith angle sun ≤ 80°. Skylight near the horizon is orange resulting from wavelength-dependent scattering by air molecules and aerosol particles through a long oblique path through the atmosphere when the sun is low in the sky (sun ≥ 85°). Halos (and coronas) seen through clouds facing the sun are brightest for cloud optical depth τcld ≈ cos(sun), and fade to obscurity for τcld ≥ 5. Rainbows (and glories), seen by light that is backscattered from clouds, also appear most dramatic when 0.2 ≤ τcld ≤ 1, but remain visible even in the thickest clouds.}, language = {en} } @article{Vollmer2005, author = {Vollmer, Michael}, title = {Effects of absorbing particles on coronas and glories}, series = {In: Applied optics 44 (2005) 27, 5658-5666}, journal = {In: Applied optics 44 (2005) 27, 5658-5666}, doi = {10.1364/AO.44.005658}, pages = {5658 -- 5666}, year = {2005}, abstract = {Light scattering from small particles changes if the particles are absorbing. Whereas the effect is small for coronas and Bishop's ring, glories show pronounced attenuation with increasing absorption. Results indicate suitable wavelength regions for studies of glory scattering from cloud tops. The behavior of core-shell particles could have applications for studying the atmosphere of Venus; in addition it provides more insight into the simple ray-path model of the glory. © 2005 Optical Society of America}, language = {en} } @inproceedings{ChristmannVollmer2004, author = {Christmann, S. and Vollmer, Michael}, title = {Jahrgangs{\"u}bergreifendes Projekt zum Wetter f{\"u}r die Grundschule}, series = {In: Didaktik der Physik : Beitr{\"a}ge zur Fr{\"u}hjahrstagung D{\"u}sseldorf 2004 ; CD zur Fr{\"u}hjahrstagung des Fachverbandes Didaktik der Physik in der Deutschen Physikalischen Gesellschaft / V. Nordmeier ... (Hrsg.). - Berlin : Lehmanns Media, 2004. - 1 CD-ROM. - ISBN 3-86541-066-9}, booktitle = {In: Didaktik der Physik : Beitr{\"a}ge zur Fr{\"u}hjahrstagung D{\"u}sseldorf 2004 ; CD zur Fr{\"u}hjahrstagung des Fachverbandes Didaktik der Physik in der Deutschen Physikalischen Gesellschaft / V. Nordmeier ... (Hrsg.). - Berlin : Lehmanns Media, 2004. - 1 CD-ROM. - ISBN 3-86541-066-9}, year = {2004}, language = {de} } @article{GedzelmanVollmer2011, author = {Gedzelman, Stanley David and Vollmer, Michael}, title = {Crepuscular rays: laboratory experiments and simulations}, series = {In: Applied Optics Vol. 50 (2011) 28, pp. F142-F151}, journal = {In: Applied Optics Vol. 50 (2011) 28, pp. F142-F151}, doi = {http://dx.doi.org/10.1364/AO.50.00F142}, year = {2011}, abstract = {Model simulations of laboratory-generated and natural crepuscular rays are presented. Rays are created in the laboratory with parallel light beams that pass through artificial fogs and milk-water solutions. Light scattered by 90° in a dilute mixture of whole milk first increases in intensity with distance from the source to a maximum as a result of multiple scattering by mainly small angles before decreasing exponentially due to extinction as distance continues to increase. Crepuscular rays are simulated for three cloud configurations. In case 1, the Sun at the zenith is blocked by a cloud with an overhanging anvil. The rays appear white against blue sky and are brightest when atmospheric turbidity, β≈11 . Shading by the anvil separates maximum brightness from apparent cloud edge. In case 2, a ray passes through a rectangular gap in a cloud layer. The ray is faint blue in a molecular atmosphere but turns pale yellow as β and solar zenith angle, ϕsun , increase. At ϕsun=60° it appears most striking when the cloud is optically thick, β≈5 , and the beam width Δx≈1000 m . In these cases, increasing aerosol radius, raer , to about 1000 nm brightens, narrows, and shortens rays. In case 3, the twilight Sun is shaded by a towering cloud or mountain. The shaded rays are deeper blue than the sunlit sky because the light originates higher in the atmosphere, where short waves have suffered less depletion from scattering. The long optical path taken by sunlight at twilight makes color and lighting contrasts of the rays greatest when the air is quite clean, i.e., for β-1≪1 . In all cases, the brightest rays occur when sunlight passes through an optical thickness of atmosphere, τ≈O(1) . © 2011 Optical Society of America}, language = {en} } @article{VollmerMoellmann2011, author = {Vollmer, Michael and M{\"o}llmann, Klaus-Peter}, title = {Rainbows, water droplets, and seeing—slow motion analysis of experiments in atmospheric optics}, series = {In: Applied optics Vol. 50 (2011) 28, pp. F21-F28}, journal = {In: Applied optics Vol. 50 (2011) 28, pp. F21-F28}, doi = {http://dx.doi.org/10.1364/AO.50.000F21}, pages = {F21 -- F28}, year = {2011}, abstract = {Many physics processes underlying phenomena in atmospheric optics happen on a rather short time scale such that neither the human eye nor video cameras are able to analyze the details. We report applications of high-speed imaging of laboratory experiments in atmospheric optics with subsequent slow motion analysis. The potential to study respective transient effects is investigated in general and for a few phenomena in detail, in particular for rainbow scattering due to single oscillating droplets during free fall, and for light propagation effects through atmospheric paths with turbulences, leading, e.g., to scintillation of stars or shimmering of mirage images. © 2011 Optical Society of America}, language = {en} } @inproceedings{VollmerPinnoMoellmann2010, author = {Vollmer, Michael and Pinno, Frank and M{\"o}llmann, Klaus-Peter}, title = {Measurements of sun and moon with IR cameras: effects of air mass}, series = {In: InfraMation proceedings. - Vol. 11 ( 2010) , 57-74}, booktitle = {In: InfraMation proceedings. - Vol. 11 ( 2010) , 57-74}, pages = {74}, year = {2010}, language = {en} } @inproceedings{MoellmannPinnoVollmer2010, author = {M{\"o}llmann, Klaus-Peter and Pinno, Frank and Vollmer, Michael}, title = {Two-color or ratio thermal imaging - potentials and limits}, series = {In: InfraMation proceedings. - Vol. 11 (2010), pp.41-56}, booktitle = {In: InfraMation proceedings. - Vol. 11 (2010), pp.41-56}, pages = {41 -- 56}, year = {2010}, language = {en} } @inproceedings{PinnoVollmerMoellmann2010, author = {Pinno, Frank and Vollmer, Michael and M{\"o}llmann, Klaus-Peter}, title = {Improved sensitivity for blower door thermography using image subtraction}, series = {In: InfraMation proceedings. - Vol. 11 (2010), p. 29-40}, booktitle = {In: InfraMation proceedings. - Vol. 11 (2010), p. 29-40}, pages = {29 -- 40}, year = {2010}, language = {en} } @inproceedings{VollmerMoellmann2010, author = {Vollmer, Michael and M{\"o}llmann, Klaus-Peter}, title = {New book on IR imaging: the ultimate resource for all users}, series = {In: InfraMation proceedings. - Vol. 11 (2010), pp 75-80}, booktitle = {In: InfraMation proceedings. - Vol. 11 (2010), pp 75-80}, pages = {75 -- 80}, year = {2010}, language = {en} } @inproceedings{VollmerMoellmann2009, author = {Vollmer, Michael and M{\"o}llmann, Klaus-Peter}, title = {IR imaging of gases: potential applications for CO2 cameras}, series = {In: InfraMation proceedings. - Vol. 10 (2009), p.113-124}, booktitle = {In: InfraMation proceedings. - Vol. 10 (2009), p.113-124}, pages = {113 -- 124}, year = {2009}, language = {en} } @inproceedings{VollmerMoellmann2009, author = {Vollmer, Michael and M{\"o}llmann, Klaus-Peter}, title = {IR imaging of gases: quantitative analysis}, series = {In: InfraMation proceedings. - Vol. 10 (2009), p. 99-112}, booktitle = {In: InfraMation proceedings. - Vol. 10 (2009), p. 99-112}, pages = {99 -- 112}, year = {2009}, language = {en} } @inproceedings{VollmerVujkovićTrelluetal.2009, author = {Vollmer, Michael and Vujković, M. and Trellu, Y. and M{\"o}llmann, Klaus-Peter}, title = {IR feedback loops to spotlights: thermography and contemporary dancing}, series = {In: InfraMation proceedings.- Vol. 10 (2009), p. 89-97}, booktitle = {In: InfraMation proceedings.- Vol. 10 (2009), p. 89-97}, pages = {89 -- 97}, year = {2009}, language = {en} } @inproceedings{PinnoMoellmannVollmer2009, author = {Pinno, Frank and M{\"o}llmann, Klaus-Peter and Vollmer, Michael}, title = {Solar load and reflection effects and respective time constants in outdoor building inspections}, series = {In: Inframation proceedings Vol. 10 (2009), 319-330}, booktitle = {In: Inframation proceedings Vol. 10 (2009), 319-330}, pages = {319 -- 330}, year = {2009}, language = {en} }