Daniel M. Neumark opened discussion of the paper by Ralf I. Kaiser: Is there any evidence for the phenylethynyl radical in the interstellar medium, and is there a plausible mechanism for its formation? Ralf I. Kaiser replied: So far, the phenylethynyl radical has not been detecte

Viet Le Duc opened a discussion of the paper by Kang-Kuen Ni: How will the relative orientation between two different KRb molecules affect the outcome of the nuclear spin coupling measurement? Will this measurement be done directly or indirectly, and if indirectly, will there be any contributio

Jan Fingerhut opened discussion of the paper by Gilbert M. Nathanson: Measuring angular distributions of evaporating He from a cylindrical jet is probably difficult or impossible. However, I wonder if people already measured angular distributions for evaporated helium in the past or if it would

, metastable atoms or antihydrogen atoms.

Daniel M. Neumark opened discussion of the paper by Ralf I. Kaiser: Is there any evidence for the phenylethynyl radical in the interstellar medium, and is there a plausible mechanism for its formation? Ralf I. Kaiser replied: So far, the phenylethynyl radical has not been detecte

Viet Le Duc opened a discussion of the paper by Kang-Kuen Ni: How will the relative orientation between two different KRb molecules affect the outcome of the nuclear spin coupling measurement? Will this measurement be done directly or indirectly, and if indirectly, will there be any contributio

Jan Fingerhut opened discussion of the paper by Gilbert M. Nathanson: Measuring angular distributions of evaporating He from a cylindrical jet is probably difficult or impossible. However, I wonder if people already measured angular distributions for evaporated helium in the past or if it would

, metastable atoms or antihydrogen atoms.

is the only electronic ground-state triatomic system possessing an Efimov state in addition to the ro-vibrational ground state. Classical methods to select and manipulate these clusters by interaction with a solid surface fail due to their exceedingly fragile bonds. Quantum reflection under grazing incidence conditions was demonstrated as a viable tool for elastic scattering from a solid surface but suffers from small reflection probabilities for typical conditions. Here we demonstrate that multiple-edge diffraction enables enhanced elastic scattering of the clusters from a solid. A dual-period reflection grating, where the strips consist of micro-structured edge arrays, shows an up to ten fold increased reflection probability as compared to its conventional counterpart where the strips are plane patches enabling quantum reflection of the clusters. The observed diffraction patterns of the clusters provide evidence of the coherent and elastic nature of scattering by multiple-edge diffraction.

Thermal-energy atom scattering at a surface under grazing incidence conditions is an innovative method for investigating dispersive atom-surface interactions with potential application in quantum sensing interferometry. The complete establishment of this technique requires a detailed peak analysis, which is yet to be achieved. We examine peak-width fluctuations in atomic and molecular beams diffracted by a grating under grazing incidence conditions. Careful measurements and analyses of the diffraction patterns of He atoms and ${\mathrm{D}}_2$ molecules from three square-wave gratings with different periods and radii of curvature enable the identification of factors influencing the peak-width variations as a function of incidence angle. The effects of macroscopic surface curvature, grating magnification, and beam emergence are substantial under these conditions but negligible for incidence angles close to the normal. Our results shed light on the phenomena occurring in grazing incidence thermal-energy atom scattering.

Thermal energy atom scattering at a surface with grazing incidence conditions is an innovative method for investigating dispersive atom-surface interactions with potential application in quantum sensing interferometry. The complete establishment of this technique would require a detailed peak analysis, which has yet to be achieved. We examined peak-width fluctuations in atomic and molecular beams diffracted by a grating under grazing incidence conditions. Careful measurements and analyses of the diffraction patterns of He atoms and D${}_2$ molecules from three square-wave gratings with different periods and radii of curvature enabled the identification of factors influencing the variations in the width as a function of the grazing incidence angle. The effects of macroscopic surface curvature, grating magnification, and beam emergence are substantial under these conditions but negligible for incidence angles close to the normal. Our results shed light on the phenomena occurring in grazing incidence thermal energy atom scattering.

We report on an experimental test of Babinet's principle in quantum reflection of an atom beam from diffraction gratings. The He beam is reflected and diffracted from a square-wave grating at near grazing-incidence conditions. According to Babinet's principle the diffraction peak intensities (except for the specular-reflected beam) are expected to be identical for any pair of gratings of complementary geometry. We observe conditions where Babinet's principle holds and also where it fails. Our data indicate breakdown conditions when either the incident or a diffracted beam propagates close to the grating surface. At these conditions, the incident or the diffracted He beam is strongly affected by the dispersive interaction between the atoms and the grating surface. Babinet's principle is also found to break down, when the complementary grating pair shows a large asymmetry in the strip widths. For very small strip widths, edge diffraction from half planes becomes dominant, whereas for the complementary wide strips the atom-surface interactions leads to a strong reduction of all non-specular diffraction peak intensities.

molecules in their lowest few rotational states are adiabatically aligned and transversely accelerated by a nonresonant optical standing wave. The width of the measured transverse velocity distribution increases to 160 m/s with the field intensity, while its central peak position moves from 10 to -10 m/s. These changes are well reproduced by numerical simulations based on the rotational state-dependent alignment but cannot be modeled when ignoring these effects. Moreover, the molecular scattering by an off-resonant optical field amounts to manipulating the translational motion of molecules in a rotational state-specific way. Conversely, our results demonstrate that scattering from a nonresonant optical standing wave is a viable method for rotational state selection of nonpolar molecules.