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Book ; Online ; Thesis: Experimentelle und theoretische Methoden zur Untersuchung von Terahertz-Spektren wässriger Lösungen

Funkner, Stefan

die Interaktion von Wasser, monoatomaren Ionen und Harnstoff im Wasserstoffbrückennetzwerk

2013

Author's details	vorgelegt von Stefan Funkner
Language	German
Size	Online-Ressource (PDF-Datei: 135 S., 2896 KB)
Publisher	Univ.-Bibliothek
Publishing place	Bochum
Document type	Book ; Online ; Thesis
Thesis / German Habilitation thesis	Univ., Diss.--Bochum, 2011
Database	Library catalogue of the German National Library of Science and Technology (TIB), Hannover

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Article ; Online: Revealing the dynamics of ultrarelativistic non-equilibrium many-electron systems with phase space tomography.

Funkner, Stefan / Niehues, Gudrun / Nasse, Michael J / Bründermann, Erik / Caselle, Michele / Kehrer, Benjamin / Rota, Lorenzo / Schönfeldt, Patrik / Schuh, Marcel / Steffen, Bernd / Steinmann, Johannes L / Weber, Marc / Müller, Anke-Susanne

Scientific reports

2023 Volume 13, Issue 1, Page(s) 4618

Abstract: The description of physical processes with many-particle systems is a key approach to the modeling of numerous physical systems. For example in storage rings, where ultrarelativistic particles are agglomerated in dense bunches, the modeling and ... ...

Abstract	The description of physical processes with many-particle systems is a key approach to the modeling of numerous physical systems. For example in storage rings, where ultrarelativistic particles are agglomerated in dense bunches, the modeling and measurement of their phase-space distribution is of paramount importance: at any time the phase-space distribution not only determines the complete space-time evolution but also provides fundamental performance characteristics for storage ring operation. Here, we demonstrate a non-destructive tomographic imaging technique for the 2D longitudinal phase-space distribution of ultrarelativistic electron bunches. For this purpose, we utilize a unique setup, which streams turn-by-turn near-field measurements of bunch profiles at MHz repetition rates. To demonstrate the feasibility of our method, we induce a non-equilibrium state and show that the phase-space distribution microstructuring as well as the phase-space distribution dynamics can be observed in great detail. Our approach offers a pathway to control ultrashort bunches and supports, as one example, the development of compact accelerators with low energy footprints.
Language	English
Publishing date	2023-03-21
Publishing country	England
Document type	Journal Article
ZDB-ID	2615211-3
ISSN	2045-2322 ; 2045-2322
ISSN (online)	2045-2322
ISSN	2045-2322
DOI	10.1038/s41598-023-31196-5
Database	MEDical Literature Analysis and Retrieval System OnLINE

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Article: Urea, a Structure Breaker? Answers from THz Absorption Spectroscopy

Funkner, Stefan / Havenith Martina / Schwaab Gerhard

Journal of physical chemistry. 2012 Nov. 15, v. 116, no. 45

2012

Abstract: There has been a controversial debate of whether urea can be regarded as structure breaker or a structure maker. Here, we present concentration and temperature dependent absorption coefficients of ureaâwater mixtures in the THz range (1.5â10 THz, 50â ...

Abstract	There has been a controversial debate of whether urea can be regarded as structure breaker or a structure maker. Here, we present concentration and temperature dependent absorption coefficients of ureaâwater mixtures in the THz range (1.5â10 THz, 50â350 cmâÂ¹). Our results are in agreement with the hypothesis that urea adapts ideally into the water network. Using a semi-ideal chemical association model and accompanying MD simulations, the observed spectra could be decomposed in three contributions: one is attributed to bulk water, a second one to rattling modes of weakly solvated urea in the surrounding water cage, and the third part accounts for THz modes describing a doubly hydrogen bonded strong solventâsolute interaction. The bands attributed to the rattling motion of the solute scale linearly with concentration. The intensity of this contribution is temperature independent in contrast to the water and strongly solvated solute absorption. We find that even at high urea concentrations the majority of water retains a bulklike absorption spectrum, whereas only a small number (about 0.5â1.1 per urea on average) are strongly bound in the temperature range between 9 and 36 Â°C. The THz absorption data provide no evidence for urea aggregation in the concentration range investigated (1â10 M).
Keywords	absorption ; cages ; hydrogen bonding ; models ; solutes ; spectroscopy ; temperature ; urea
Language	English
Dates of publication	2012-1115
Size	p. 13374-13380.
Publishing place	American Chemical Society
Document type	Article
ISSN	1520-5207
DOI	10.1021%2Fjp308699w
Database	NAL-Catalogue (AGRICOLA)

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Article ; Online: Urea, a structure breaker? Answers from THz absorption spectroscopy.

Funkner, Stefan / Havenith, Martina / Schwaab, Gerhard

The journal of physical chemistry. B

2012 Volume 116, Issue 45, Page(s) 13374–13380

Abstract: There has been a controversial debate of whether urea can be regarded as structure breaker or a structure maker. Here, we present concentration and temperature dependent absorption coefficients of urea-water mixtures in the THz range (1.5-10 THz, 50-350 ... ...

Abstract	There has been a controversial debate of whether urea can be regarded as structure breaker or a structure maker. Here, we present concentration and temperature dependent absorption coefficients of urea-water mixtures in the THz range (1.5-10 THz, 50-350 cm(-1)). Our results are in agreement with the hypothesis that urea adapts ideally into the water network. Using a semi-ideal chemical association model and accompanying MD simulations, the observed spectra could be decomposed in three contributions: one is attributed to bulk water, a second one to rattling modes of weakly solvated urea in the surrounding water cage, and the third part accounts for THz modes describing a doubly hydrogen bonded strong solvent-solute interaction. The bands attributed to the rattling motion of the solute scale linearly with concentration. The intensity of this contribution is temperature independent in contrast to the water and strongly solvated solute absorption. We find that even at high urea concentrations the majority of water retains a bulklike absorption spectrum, whereas only a small number (about 0.5-1.1 per urea on average) are strongly bound in the temperature range between 9 and 36 °C. The THz absorption data provide no evidence for urea aggregation in the concentration range investigated (1-10 M).
MeSH term(s)	Fourier Analysis ; Molecular Dynamics Simulation ; Spectrum Analysis/methods ; Urea/chemistry
Chemical Substances	Urea (8W8T17847W)
Language	English
Publishing date	2012-11-15
Publishing country	United States
Document type	Journal Article
ISSN	1520-5207
ISSN (online)	1520-5207
DOI	10.1021/jp308699w
Database	MEDical Literature Analysis and Retrieval System OnLINE

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Article ; Online: Communications: Polarity fluctuations of the protic ionic liquid ethylammonium nitrate in the terahertz regime.

Krüger, Matthias / Bründermann, Erik / Funkner, Stefan / Weingärtner, Hermann / Havenith, Martina

The Journal of chemical physics

2010 Volume 132, Issue 10, Page(s) 101101

Abstract: We have measured the complex dielectric function of the protic ionic liquid ethylammonium nitrate in the frequency range between 0.15 and 1.8 THz with a terahertz time domain spectrometer. The experiments reveal a terahertz mode which can be described as ...

Abstract	We have measured the complex dielectric function of the protic ionic liquid ethylammonium nitrate in the frequency range between 0.15 and 1.8 THz with a terahertz time domain spectrometer. The experiments reveal a terahertz mode which can be described as a damped harmonic oscillator with a central frequency of 1.3 THz. The terahertz mode is assigned to an intermolecular vibration, presumably associated with hydrogen-bond dynamics. The data are combined with microwave data to represent the dielectric spectrum from quasistatic conditions up to 1.8 THz.
Language	English
Publishing date	2010-03-14
Publishing country	United States
Document type	Journal Article
ZDB-ID	3113-6
ISSN	1089-7690 ; 0021-9606
ISSN (online)	1089-7690
ISSN	0021-9606
DOI	10.1063/1.3352585
Database	MEDical Literature Analysis and Retrieval System OnLINE

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Article ; Online: A matter of symmetry: terahertz polarization detection properties of a multi-contact photoconductive antenna evaluated by a response matrix analysis.

Niehues, Gudrun / Funkner, Stefan / Bulgarevich, Dmitry S / Tsuzuki, Satoshi / Furuya, Takashi / Yamamoto, Koji / Shiwa, Mitsuharu / Tani, Masahiko

Optics express

2015 Volume 23, Issue 12, Page(s) 16184–16195

Abstract: While terahertz time domain spectroscopy (THz-TDS) is a well-established technique, polarization sensitive measurements are challenging due to the need of broadband polarization devices. Here, we characterize our recently introduced multi-contact ... ...

Abstract	While terahertz time domain spectroscopy (THz-TDS) is a well-established technique, polarization sensitive measurements are challenging due to the need of broadband polarization devices. Here, we characterize our recently introduced multi-contact photoconductive detector antenna with a response matrix analysis. We show that the lead lines attached to electrodes reduce the antenna symmetry and thereby influence the properties of the response matrices. With a wire grid polarizer, we simulate a sample influencing the polarization angle and the intensity of the incident THz pulse. Evaluating the measurements with the response matrix analysis, our results show a well agreement of the adjusted and measured polarization angles and intensities over a frequency range from 0.25 to 0.8 THz.
Language	English
Publishing date	2015-06-15
Publishing country	United States
Document type	Journal Article
ZDB-ID	1491859-6
ISSN	1094-4087 ; 1094-4087
ISSN (online)	1094-4087
ISSN	1094-4087
DOI	10.1364/OE.23.016184
Database	MEDical Literature Analysis and Retrieval System OnLINE

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Article ; Online: From self-organization in relativistic electron bunches to coherent synchrotron light: observation using a photonic time-stretch digitizer.

Bielawski, Serge / Blomley, Edmund / Brosi, Miriam / Bründermann, Erik / Burkard, Eva / Evain, Clément / Funkner, Stefan / Hiller, Nicole / Nasse, Michael J / Niehues, Gudrun / Roussel, Eléonore / Schedler, Manuel / Schönfeldt, Patrik / Steinmann, Johannes L / Szwaj, Christophe / Walther, Sophie / Müller, Anke-Susanne

Scientific reports

2019 Volume 9, Issue 1, Page(s) 10391

Abstract: In recent and future synchrotron radiation facilities, relativistic electron bunches with increasingly high charge density are needed for producing brilliant light at various wavelengths, from X-rays to terahertz. In such conditions, interaction of ... ...

Abstract	In recent and future synchrotron radiation facilities, relativistic electron bunches with increasingly high charge density are needed for producing brilliant light at various wavelengths, from X-rays to terahertz. In such conditions, interaction of electron bunches with their own emitted electromagnetic fields leads to instabilities and spontaneous formation of complex spatial structures. Understanding these instabilities is therefore key in most electron accelerators. However, investigations suffer from the lack of non-destructive recording tools for electron bunch shapes. In storage rings, most studies thus focus on the resulting emitted radiation. Here, we present measurements of the electric field in the immediate vicinity of the electron bunch in a storage ring, over many turns. For recording the ultrafast electric field, we designed a photonic time-stretch analog-to-digital converter with terasamples/second acquisition rate. We could thus observe the predicted link between spontaneous pattern formation and giant bursts of coherent synchrotron radiation in a storage ring.
Language	English
Publishing date	2019-07-17
Publishing country	England
Document type	Journal Article
ZDB-ID	2615211-3
ISSN	2045-2322 ; 2045-2322
ISSN (online)	2045-2322
ISSN	2045-2322
DOI	10.1038/s41598-019-45024-2
Database	MEDical Literature Analysis and Retrieval System OnLINE

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Article: Dissecting the THz spectrum of liquid water from first principles via correlations in time and space

Heyden, Matthias / Sun, Jian / Funkner, Stefan / Mathias, Gerald / Forbert, Harald / Havenith, Martina / Marx, Dominik

Proceedings of the National Academy of Sciences of the United States of America. 2010 July 6, v. 107, no. 27

2010

Abstract: Solvation of molecules in water is at the heart of a myriad of molecular phenomena and of crucial importance to understanding such diverse issues as chemical reactivity or biomolecular function. Complementing well-established approaches, it has been ... ...

Abstract	Solvation of molecules in water is at the heart of a myriad of molecular phenomena and of crucial importance to understanding such diverse issues as chemical reactivity or biomolecular function. Complementing well-established approaches, it has been shown that laser spectroscopy in the THz frequency domain offers new insights into hydration from small solutes to proteins. Upon introducing spatially-resolved analyses of the absorption cross section by simulations, the sensitivity of THz spectroscopy is traced back to characteristic distance-dependent modulations of absorption intensities for bulk water. The prominent peak at [almost equal to]200 cm⁻¹ is dominated by first-shell dynamics, whereas a concerted motion involving the second solvation shell contributes most significantly to the absorption at about 80 cm⁻¹ [almost equal to]2.4 THz. The latter can be understood in terms of an umbrella-like motion of two hydrogen-bonded tetrahedra along the connecting hydrogen bond axis. Thus, a modification of the hydrogen bond network, e.g., due to the presence of a solute, is expected to affect vibrational motion and THz absorption intensity at least on a length scale that corresponds to two layers of solvating water molecules. This result provides a molecular mechanism explaining the experimentally determined sensitivity of absorption changes in the THz domain in terms of distinct, solute-induced dynamical properties in solvation shells of (bio)molecules--even in the absence of well-defined resonances.
Keywords	absorption ; hydrogen bonding ; proteins ; solutes ; space and time ; spectroscopy
Language	English
Dates of publication	2010-0706
Size	p. 12068-12073.
Publishing place	National Academy of Sciences
Document type	Article
ZDB-ID	209104-5
ISSN	1091-6490 ; 0027-8424
ISSN (online)	1091-6490
ISSN	0027-8424
DOI	10.1073/pnas.0914885107
Database	NAL-Catalogue (AGRICOLA)

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Article ; Online: Dissecting the THz spectrum of liquid water from first principles via correlations in time and space.

Heyden, Matthias / Sun, Jian / Funkner, Stefan / Mathias, Gerald / Forbert, Harald / Havenith, Martina / Marx, Dominik

Proceedings of the National Academy of Sciences of the United States of America

2010 Volume 107, Issue 27, Page(s) 12068–12073

Abstract	Solvation of molecules in water is at the heart of a myriad of molecular phenomena and of crucial importance to understanding such diverse issues as chemical reactivity or biomolecular function. Complementing well-established approaches, it has been shown that laser spectroscopy in the THz frequency domain offers new insights into hydration from small solutes to proteins. Upon introducing spatially-resolved analyses of the absorption cross section by simulations, the sensitivity of THz spectroscopy is traced back to characteristic distance-dependent modulations of absorption intensities for bulk water. The prominent peak at approximately 200 cm(-1) is dominated by first-shell dynamics, whereas a concerted motion involving the second solvation shell contributes most significantly to the absorption at about 80 cm(-1) approximately 2.4 THz. The latter can be understood in terms of an umbrella-like motion of two hydrogen-bonded tetrahedra along the connecting hydrogen bond axis. Thus, a modification of the hydrogen bond network, e.g., due to the presence of a solute, is expected to affect vibrational motion and THz absorption intensity at least on a length scale that corresponds to two layers of solvating water molecules. This result provides a molecular mechanism explaining the experimentally determined sensitivity of absorption changes in the THz domain in terms of distinct, solute-induced dynamical properties in solvation shells of (bio)molecules--even in the absence of well-defined resonances.
MeSH term(s)	Algorithms ; Computer Simulation ; Kinetics ; Models, Chemical ; Solutions/chemistry ; Spectrophotometry, Infrared/methods ; Time Factors ; Water/chemistry
Chemical Substances	Solutions ; Water (059QF0KO0R)
Language	English
Publishing date	2010-06-21
Publishing country	United States
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	209104-5
ISSN	1091-6490 ; 0027-8424
ISSN (online)	1091-6490
ISSN	0027-8424
DOI	10.1073/pnas.0914885107
Database	MEDical Literature Analysis and Retrieval System OnLINE

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Article ; Online: Low temperature-grown GaAs carrier lifetime evaluation by double optical pump terahertz time-domain emission spectroscopy.

Mag-Usara, Valynn Katrine / Funkner, Stefan / Niehues, Gudrun / Prieto, Elizabeth Ann / Balgos, Maria Herminia / Somintac, Armando / Estacio, Elmer / Salvador, Arnel / Yamamoto, Kohji / Hase, Muneaki / Tani, Masahiko

Optics express

2016 Volume 24, Issue 23, Page(s) 26175–26185

Abstract: We present the use of a "double optical pump" technique in terahertz time-domain emission spectroscopy as an alternative method to investigate the lifetime of photo-excited carriers in semiconductors. Compared to the commonly employed optical pump-probe ... ...

Abstract	We present the use of a "double optical pump" technique in terahertz time-domain emission spectroscopy as an alternative method to investigate the lifetime of photo-excited carriers in semiconductors. Compared to the commonly employed optical pump-probe transient photo-reflectance, this non-contact and room temperature characterization technique allows relative ease in achieving optical alignment. The technique was implemented to evaluate the carrier lifetime in low temperature-grown gallium arsenide (LT-GaAs). The carrier lifetime values deduced from "double optical pump" THz emission decay curves show good agreement with data obtained from standard transient photo-reflectance measurements on the same LT-GaAs samples grown at 250 °C and 310 °C.
Language	English
Publishing date	2016-11-14
Publishing country	United States
Document type	Journal Article
ZDB-ID	1491859-6
ISSN	1094-4087 ; 1094-4087
ISSN (online)	1094-4087
ISSN	1094-4087
DOI	10.1364/OE.24.026175
Database	MEDical Literature Analysis and Retrieval System OnLINE

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