High-Resolution Helium Atom Time-of-Flight Spectroscopy of Low-Frequency Vibrations of Adsorbates

Hofmann, F.; Jp, Toennies

doi:10.1021/cr9502209

Cited by 149 publications

(109 citation statements)

References 134 publications

(232 reference statements)

Supporting

Mentioning

107

Contrasting

Unclassified

Order By: Relevance

“…Several dozen machines have subsequently been built along the lines of the machine that Bruce put together. In our group, not only were we able to measure the surface phonon-dispersion curves of more than 100 different insulators, semiconductors, and metals, but we also observed a number of new phenomena such as low-frequency (h − ω ≤ 10 meV) adsorbate vibrations, not previously accessible (36), and the dynamics of diffusing atoms and molecules for a large number of adsorbate-surface combinations (37).…”

Section: Time-of-flight Spectroscopy Of Surface Phononsmentioning

confidence: 92%

Serendipitous Meanderings and Adventures With Molecular Beams

Toennies¹

2004

Annu. Rev. Phys. Chem.

Self Cite

View full text Add to dashboard Cite

s Abstract This is the story of a native-born American who came as a postdoc to the country of his parents, Germany. There, by good fortune, he could participate in the revival and the rebuilding of the physical sciences following the ravishments of the Second World War, becoming at the age of 38, the director of a Max-Planck-Institut in Göttingen. Working under nearly ideal conditions, he carried out basic research using molecular beams. Aided by many active, youthfully impulsive, yet perceptive and imaginative, students and experienced knowledgeable guest scientists from many countries, he enjoyed exciting adventures into unknown landscapes in the fields of molecular gas-phase interactions and solid-surface phenomena and, most recently, in the realms of quantum liquids and solids.

show abstract

Section: Time-of-flight Spectroscopy Of Surface Phononsmentioning

confidence: 92%

Serendipitous Meanderings and Adventures With Molecular Beams

Toennies¹

2004

Annu. Rev. Phys. Chem.

Self Cite

View full text Add to dashboard Cite

show abstract

“…The T-mode is known to appear when the adparticle moves between two stable positions at the surface within one adsorption site (for instance, between the atop position and the saddle point [3]) due to interaction with phonons or electronic subsystem of the substrate. This motion of the adsorbate is being detected during inelastic helium atom scattering (IHAS) [6,7] as an additional peak in the dynamic structure factor [5,8,9]. The vibrational nature of the Tmode allows to refer this excitation to the external (low frequency) modes of the adsorbate [10,11], which are more or less temperature dependent and dispersionless with homogeneous broadening at low coverages [5].…”

Section: Introductionmentioning

confidence: 99%

A temperature behavior of the frustrated translational mode of adsorbate and the nature of the “adsorbate–substrate” interaction

Ignatyuk

2012

The Journal of Chemical Physics

View full text Add to dashboard Cite

A temperature behavior of the frustrated translational mode of adsorbate and the nature of the "adsorbate-substrate" interaction V.V. IgnatyukInstitute for Condensed Matter Physics, 1 Svientsitskii Street, 79011, Lviv, Ukraine (Dated: August 6, 2017)A temperature behavior of the frustrated translational mode (T-mode) of a light particle, coupled by different regimes of ohmicity to the surface, is studied within a formalism of the generalized diffusion coefficients. The memory effects of the adsorbate motion are considered to be the main reason of the T-mode origin. Numerical calculations yield a thermally induced shift and broadening of the T-mode, which is found to be linear in temperature for Ohmic and super-Ohmic systems and nonlinear for strongly sub-Ohmic ones. We obtain analytical expressions for the T-mode shift and width at weak coupling for the systems with integer "ohmicity" indexes n = 0÷2 in zero temperature and high temperature limits. We provide an explanation of the experimentally observed blue-or red-shifts of the T-mode on the basis of a comparative analysis of two typical times of the system evolution: a time of decay of the "velocity-velocity" autocorrelation function, and a correlation time of the thermal bath random forces. A relation of the T-mode to the multiple jumps of the adsorbate is discussed, and generalization of conditions of the multiple hopping to the case of quantum surface diffusion is performed.

show abstract

“…For example, they are well established in techniques for the investigation of surface structure and dynamics in reciprocal space 3 and enable the measurement of interaction potentials between molecules and surfaces. 4 Other applications of molecular beams include the study of interaction potentials between molecules. 5,6 For the focusing of such beams the primary goal is to create a microscope that uses neutral particles as an imaging probe.…”

Section: Introductionmentioning

confidence: 99%

Neutral atom and molecule focusing using a Fresnel zone plate

Reisinger

Holst

2008

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

View full text Add to dashboard Cite

Focusing of neutral atoms and molecules has several potential applications. The very first microscopy images using helium as an imaging probe were published earlier this year. Another possible application is to study the diffusion of atoms and molecules through materials with high spatial resolution by stepping a porous or permeable sample across the focused beam. With this application in mind, the authors present the best resolution transmission images hitherto achieved with helium atoms ͑less than 2 m͒ of a thin carbon film with 2 m holes. Furthermore, they present the first experiment using a Fresnel zone plate to focus neutral molecules. They used a beam of deuterium ͑D 2 ͒ which was focused down to 15.2Ϯ 0.5 m. D 2 was chosen because it fits in mass to the geometry of our system, which is optimized for helium. However, the method can be extended to hydrogen ͑H 2 ͒ or other molecules by using a suitably adapted zone plate. In both cases the focus was limited by chromatic aberrations, caused by the velocity spread of the beams. Finally, they present calculations exploring the resolution limits for focusing of molecular beams using Fresnel zone plates. The calculations show that Fresnel focusing down to 170 nm full width at half maximum is possible with presently available techniques.

show abstract

High-Resolution Helium Atom Time-of-Flight Spectroscopy of Low-Frequency Vibrations of Adsorbates

Cited by 149 publications

References 134 publications

Serendipitous Meanderings and Adventures With Molecular Beams

Serendipitous Meanderings and Adventures With Molecular Beams

A temperature behavior of the frustrated translational mode of adsorbate and the nature of the “adsorbate–substrate” interaction

Neutral atom and molecule focusing using a Fresnel zone plate

Contact Info

Product

Resources

About