Spectroscopic Instrumentation

Demtröder, Wolfgang

doi:10.1007/978-3-662-08257-7_4

Cited by 50 publications

(71 citation statements)

References 49 publications

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“…In contrast to previous state-resolved studies, 5 we per- formed the laser excitation of the molecular beam in close proximity to target surface in order to minimize the loss of alignment by nuclear hyperfine depolarization. 19 The focal length and position of the cylindrical lens were chosen to create an IR radiation field with suitably curved wavefronts to achieve Doppler tuning through a rovibrational transition for the methane molecules as they move through the focused laser beam. This Doppler tuning in combination with a suitably strong excitation field leads to excitation via rapid adiabatic passage (RAP), 20 which allows for complete population inversion of the rovibrational transition used for excitation.…”

Section: Methodsmentioning

confidence: 99%

Alignment dependent chemisorption of vibrationally excited CH4(ν3) on Ni(100), Ni(110), and Ni(111)

Yoder

Bisson

Hundt

et al. 2011

The Journal of Chemical Physics

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Influence of quantum effects on the physisorption of molecular hydrogen in model carbon foams J. Chem. Phys. 135, 214701 (2011) Constructing a new closure theory based on the third-order Ornstein-Zernike equation and a study of the adsorption of simple fluids J. Chem. Phys. 135, 204706 (2011) Kinetic and relativistic effects on the surface alloy formation of submonolayer Au adsorbed on Si(111)-×-Pb surface Appl. Phys. Lett. 99, 211912 (2011) Kinetics of gas mediated electron beam induced etching Appl. Phys. Lett. 99, 213103 (2011) Additional information on J. Chem. Phys. We present a stereodynamics study of the dissociative chemisorption of vibrationally excited methane on the (100), (110), and (111) planes of a nickel single crystal surface. Using linearly polarized infrared excitation of the antisymmetric C-H stretch normal mode vibration (ν 3 ), we aligned the angular momentum and C-H stretch amplitude of CH 4 (ν 3 ) in the laboratory frame and measured the alignment dependence of state-resolved reactivity of CH 4 for the ν 3 = 1, J = 0-3 quantum states over a range of incident translational energies. For all three surfaces studied, in-plane alignment of the C-H stretch results in the highest dissociation probability and alignment along the surface normal in the lowest reactivity. The largest alignment contrast between the maximum and minimum reactivity is observed for Ni(110), which has its surface atoms arranged in close-packed rows separated by one layer deep troughs. For Ni(110), we also probed for alignment effects relative to the direction of the Ni rows. In-plane C-H stretch alignment perpendicular to the surface rows results in higher reactivity than parallel to the surface rows. The alignment effects on Ni(110) and Ni(100) are independent of incident translational energy between 10 and 50 kJ/mol. Quantum state-resolved reaction probabilities are reported for CH 4 (ν 3 ) on Ni(110) for translational energies between 10 and 50 kJ/mol.

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Section: Methodsmentioning

confidence: 99%

Alignment dependent chemisorption of vibrationally excited CH4(ν3) on Ni(100), Ni(110), and Ni(111)

Yoder

Bisson

Hundt

et al. 2011

The Journal of Chemical Physics

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“…The heart of experimentally testing and controlling classical and quantum systems often lies in the introduction of an external periodic driving force [1,2,3]. The driving probes system specific properties, the knowledge of which allows one, in turn, to understand and to optimally control the system at hand.…”

Section: Introductionmentioning

confidence: 99%

Experimental verification of a one-parameter scaling law for the quantum and “classical” resonances of the atom-optics kicked rotor

et al. 2005

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We present experimental measurements of the mean energy in the vicinity of the first and second quantum resonances of the atom optics kicked rotor for a number of different experimental parameters. Our data is rescaled and compared with the one parameter ǫ-classical scaling function developed to describe the quantum resonance peaks. Additionally, experimental data is presented for the "classical" resonance which occurs in the limit as the kicking period goes to zero. This resonance is found to be analogous to the quantum resonances, and a similar one-parameter classical scaling function is derived, and found to match our experimental results. The width of the quantum and classical resonance peaks is compared, and their Sub-Fourier nature examined.

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“…Noteworthy, the differential scheme is expected to perform the same in reflection, which will be simpler to implement experimentally as only one objective needs then to be aligned. The sample is modeled in space as an ensemble of voxels containing each a collection of independent oscillators and, for each sample voxel, the change in intensity due to stimulated absorption/emission [49], along the coordinate z defined as the axis of propagation of the light pulses, normal to the sample surface, is inferred from…”

Section: Modelmentioning

confidence: 99%

High resolution imaging with differential infrared absorption micro-spectroscopy

et al. 2013

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Although confocal infrared (IR) absorption micro-spectroscopy is well established for far-field chemical imaging, its scope remains restricted since diffraction limits the spatial resolution to values a little above half the radiation wavelength. Yet, the successful implementations of below-the-diffraction limit far-field fluorescence microscopies using saturated irradiation patterns for example for stimulated-emission depletion and saturated structured-illumination suggest the possibility of using a similar optical patterning strategy for infrared absorption mapping at high resolution. Simulations are used to show that the simple mapping of the difference in transmitted/reflected IR energy between a saturated vortexshaped beam and a Gaussian reference with a confocal microscope affords the generation of high-resolution vibrational absorption images. On the basis of experimentally relevant parameters, the simulations of the differential absorption scheme reveal a spatial resolution better than a tenth of the wavelength for incident energies about a decade above the saturation threshold. The saturated structured illumination concepts are thus expected to be compatible with the establishment of point-like point-spread functions for measuring the absorbance of samples with a scanning confocal microscope recording the differential transmission/reflection.

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Spectroscopic Instrumentation

Cited by 50 publications

References 49 publications

Alignment dependent chemisorption of vibrationally excited CH4(ν3) on Ni(100), Ni(110), and Ni(111)

Alignment dependent chemisorption of vibrationally excited CH4(ν3) on Ni(100), Ni(110), and Ni(111)

Experimental verification of a one-parameter scaling law for the quantum and “classical” resonances of the atom-optics kicked rotor

High resolution imaging with differential infrared absorption micro-spectroscopy

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