The potential energy curves (PECs) of the bound states of M-X (M=Cu, Ag, and Au and X=He, Ne, and Ar) complexes have been calculated using the coupled cluster singles and doubles method with perturbative treatment of triple excitations. Large basis sets and bond functions, as well as the basis set superposition errors, are employed to obtain accurate PECs. The analytical potential energy functions (APEFs) are fitted using the PECs. The vibrational energy levels and the spectroscopic parameters for the complexes are determined using our APEFs and compared to the theoretical works available at present. We also find that the PECs are bound with similar van der Waals interactions, which implies that He, Ne, and Ar may be used for buffer-gas cooling; and Cu, Ag, and Au may be trapped with a similar method because Cu and Ag have been experimentally trapped with He buffer-gas cooling.
Helium dimer in its metastable triplet electronic state, He
2(a 3Σu+), is a promising candidate for direct laser cooling and precision measurements. Interactions and collisions involving He
2(a 3Σu+) remain unexplored in ultracold and cold energy domains. Here, we present the first theoretical investigation of intermolecular interactions and collision dynamics of He
2(a 3Σu+)+Ne van der Waals complex. For the ground electronic state,
X 3A′, we employ a spin-restricted coupled cluster method with single, double, and noniterative triple excitations. The resulting interaction potential exhibits an extremely shallow well with a depth of 4.612 cm
−1. We construct a three-dimensional vibrationally averaged potential energy surface. Using this surface, we perform full close-coupling calculations including fine-structure levels of He
2(a 3Σu+) to investigate collisional excitation and quenching induced by Ne. We analyze the low-energy scattering dynamics and model resonant features associated with quasi-bound states supported by interaction potential. Propensity rule for fine-structure conserving transitions is established. We additionally consider He
2+Ar collisions and compare their energy dependence and resonance structure with those of He
2+Ne. The He
2+Ar system exhibits a richer resonance structure, highlighting the sensitivity of low-energy scattering to interaction potential and reduced mass. Calculated PES and scattering properties provide a reliable benchmark for description of He
2+Ne van der Waals complex and may be useful for interpretation of future experimental spectra and collision measurements.
The scattering of He and Ne atoms from a cleaved (001) surface of NaF has been studied at different surface temperatures and incident beam energies. The geometric peak shape expected for the beam detector arrangement was compared to the experimentally observed peaks under different conditions of surface temperature and incident energy. The (00) peak height was followed as a function of surface temperature for two values of the incident momentum, in order to extract some information about the role of the attractive part of the interaction potential during a collision. Finally, the peak heights of several diffraction peaks were determined as a function of the incident energy. Several minima were observed in the scattering pattern, which can be associated with bound state resonances and which have been the subject of considerable interest recently. In this case, several maxima were found which can also be associated with bound state resonances. The (00) peak, observed in the scattering of Ne atoms, also showed maxima and minima when the height was monitored, as a function of the incident energy.
In atom optics a material structure is commonly regarded as an amplitude mask for atom waves. However, atomic diffraction patterns formed using material gratings indicate that material structures also operate as phase masks. In this study a well collimated beam of sodium atoms is used to illuminate a silicon nitride grating with a period of 100 nm. During passage through the grating slots atoms acquire a phase shift due to the van der Waals interaction with the grating walls. As a result the relative intensities of the matter-wave diffraction peaks deviate from those expected for a purely absorbing grating. Thus a complex transmission function is required to explain the observed diffraction envelopes. An optics perspective to the theory of atomic diffraction from material gratings is put forth in the hopes of providing a more intuitive picture concerning the influence of the vdW potential. The van der Waals coefficient
C3=2.7±0.8meVnm3 is determined by fitting a modified Fresnel optical theory to the experimental data. This value of
C3 is consistent with a van der Waals interaction between atomic sodium and a silicon nitride surface.
Summary form only given. In atom optics, techniques were proposed to confine atoms in 2D waveguides utilizing light potentials or static magnetic fields on surfaces. For atoms close to the surface at distances shorter than the optical wavelength, the atoms-surface van der Waals interaction is inevitable and represents a complicating factor for these experiments. Here we propose to confine neutral atoms directly in a particular state of a surface potential well thanks to a laser induced Raman transfer connecting optical transitions of free cold atoms to the surface bound states. We numerically solve the 1D Schrodinger equation for cesium atom parameters. To populate the atom-surface long range states we consider cold Cs atoms near a dielectric surface interacting simultaneously with two resonant lasers.
In atom optics a material structure is commonly regarded as an amplitude mask for atom waves. However, atomic diffraction patterns formed using material gratings indicate that material structures also operate as phase masks. In this study a well collimated beam of sodium atoms is used to illuminate a silicon nitride grating with a period of 100 nm. During passage through the grating slots atoms acquire a phase shift due to the van der Waals interaction with the grating walls. As a result the relative intensities of the matter-wave diffraction peaks deviate from those expected for a purely absorbing grating. Thus a complex transmission function is required to explain the observed diffraction envelopes. An optics perspective to the theory of atomic diffraction from material gratings is put forth in the hopes of providing a more intuitive picture concerning the influence of the vdW potential. The van der Waals coefficient
C3=2.7pm0.8meVnm3 is determined by fitting a modified Fresnel optical theory to the experimental data. This value of
C3 is consistent with a van der Waals interaction between atomic sodium and a silicon nitride surface.