Related papers: Cold, anisotropically-interacting van der Waals mo…
We discuss theoretically ion-atom collisions at low energy and predict the possibility of formation of cold molecular ion by photoassociation. We present results on radiative homo- and hetero-nuclear atom-ion cold collisions that reveal…
Using modified Arrhenius approximations, the activation energies of water, alcohols, and hexane structure rearrangement reactions responsible for temperature dependences of their dynamic and dielectric characteristics were determined. The…
Environmental molecular beam experiments are used to examine water interactions with liquid methanol films at temperatures from 170 K to 190 K. We find that water molecules with 0.32 eV incident kinetic energy are efficiently trapped by the…
We give an overview of the experiments at the Laser Centre of the Vrije Universiteit in Amsterdam on ultracold gases of metastable helium-4 and helium-3 as well as mixtures of both isotopes. We describe our experimental setup and discuss…
We produce giant helium dimers by photoassociation of metastable helium atoms in a magnetically trapped, ultracold cloud. The photoassociation laser is detuned red of the atomic $2^3S_1 - 2^3P_0 $ line and produces strong heating of the…
We demonstrate an approach for producing a high flux beam of $^7$Li$^4$He dimers by performing post-nozzle seeding of a lithium beam into a supersonic helium expansion. The molecular beam has a longitudinal temperature of 13(6) mK and a…
We present quantum-theoretical studies of collisions between an open-shell S-state atom and a ^2Pi-state molecule in the presence of a magnetic field. We analyze the collisional Hamiltonian and discuss possible mechanisms for inelastic…
Exciton binding energies of hundreds of meV and strong light absorption in the optical frequency range make transition metal dichalcogenides (TMDs) promising for novel optoelectronic nanodevices. In particular, atomically thin TMDs can be…
We have investigated cold ionizing heteronuclear collisions in dilute mixtures of metastable (2 3S1) 3He and 4He atoms, extending our previous work on the analogous homonuclear collisions [R. J. W. Stas et al., PRA 73, 032713 (2006)]. A…
The reactions of carbon atoms with dihydrogen have been investigated in liquid helium droplets at $T$ = 0.37 K. A calorimetric technique was applied to monitor the energy released in the reaction. The barrierless reaction between a single…
We consider cold polar molecules confined in a helical optical lattice similar to those used in holographic microfabrication. An external electric field polarizes molecules along the axis of the helix. The large-distance inter-molecular…
The quantum anomalous Hall effect (QAHE) that emerges under broken time-reversal symmetry in topological insulators (TI) exhibits many fascinating physical properties for potential applications in nano-electronics and spintronics. However,…
Many predictions of Doppler cooling theory of two-level atoms have never been verified in a three-dimensional geometry, including the celebrated minimum achievable temperature $\hbar \Gamma/2 k_B$, where $\Gamma$ is the transition…
We study anisotropic thermalization in dilute gases of microwave shielded polar molecular fermions. For collision energies above the threshold regime, we find that thermalization is suppressed due to a strong preference for forward…
It has recently become possible to form molecules in ultracold gases of trapped alkali metal atoms. Once formed, the molecules may undergo elastic, inelastic and reactive collisions. Inelastic and reactive collisions are particularly…
Buffer gas cooling with a $^4$He gas is used to perform laser-absorption spectroscopy of the $^{12}$C$_2$H$_2$ ($\nu_1+\nu_3$) band at cryogenic temperatures. Doppler thermometry is first carried out to extract translational temperatures…
The formation of ultracold molecules via stimulated emission followed by a radiative deexcitation cascade in the presence of a static electric field is investigated. By analyzing the corresponding cross sections, we demonstrate the…
Cold molecules are important for many applications, from fundamental precision measurements, quantum information processing, quantum-controlled chemistry, to understanding the cold interstellar medium. Molecular ions are known to be cooled…
We studied a novel cooling method, in which $^3$He and $^4$He are mixed at the $^4$He crystallization pressure at temperatures below $0.5\,\mathrm{mK}$. We describe the experimental setup in detail, and present an analysis of its…
We report on the achievement of quantum degeneracy in both components of a Bose-Fermi mixture of metastable helium atoms, $^4$He* and $^3$He*. Degeneracy is achieved via Doppler cooling and forced evaporation for $^4$He*, and…