Water is the third most abundant molecule in the interstellar medium (ISM) and has ubiquitously been observed by ground- and space-based telescopes since its first detection in 1969 in the Orion nebula [1]. Thus water is a key molecule for the understanding of the energy balance and the physical-chemical processes that occur in these environments. Its principal collision partner obviously is...
The title reaction, widely studied both experimentally and theoretically, has become a benchmark for insertion barrierless reactions [1]. Its dynamics is considered here for collision energies of a few tens of Kelvin. In this energy regime, major quantum effects arise. The aim of the talk is to show how they can be taken into account in the classical trajectory description of the dynamics...
Context: Molecular oxygen is peculiar of Earth’s atmosphere and the precursor of stratospheric ozone which absorbs most of the Sun UV radiations. Oxygen isotopic analysis allows one to trace back the origin of elements constituting Solar system primitive materials, like meteorites and comets. O$_2$ and O$_3$ formed from $^{16}$O isotope are dominant, thereby giving a reference for any...
We propose a method to engineer repulsive long-range interactions between ultracold ground-state molecules using optical fields, thus preventing short-range collisional losses. It maps the microwave coupling recently used for collisional shielding onto a two-photon transition, and takes advantage of optical control techniques. In contrast to one-photon optical shielding [Phys. Rev. Lett....
Le refroidissement par collisions avec un gaz tampon à température cryogénique, dit refroidissement CBG (“cryogenic buffer gas” cooling), est une technique de choix pour refroidir à quelques Kelvin des molécules en phase gaz. Cette technique a été appliquée à divers types d’espèces, majoritairement des molécules diatomiques et radicaux légers, mais aussi quelques molécules plus complexes [1]....
Understanding few-body interactions remains challenging and we are usually limited to systems close to the unitary regime. Cold quantum gases can give rise to samples where isolated atoms coexist with dimers or trimers. Their low temperature allows then to perform high precision spectroscopy of the effects of interactions between the different constituents.
We report on microwave...
The real-time dynamics of DABCO-argon clusters is investigated in a femtosecond pump-probe experiment where the pump excites DABCO to the S$_1$ state within the argon cluster. The probe operates by photoionization and documents the energy and angular distributions of the resulting photoelectrons. The dynamics is followed up to 500 ps. A multiscale dynamics is observed. It includes a short...
The intense coherent X-ray pulses from short-wavelength Free-Electron Lasers (FEL) have opened up the possibility to take “snapshots” of individual free-flying nanoparticles with Coherent Diffraction Imaging (CDI), without the need to fix the samples on a substrate. In a single irradiation, especially fragile, short-lived or unique nanoscale structures, such as single viruses, aerosols, and...
In recent years, tremendous progress in the preparation and control of ultracold molecular gases in the quantum regime has been achieved and has opened exciting new research opportunities. Molecules rotate and oscillate and therefore offer many more quantum degrees of freedom than their atomic counterparts. Polar molecules interact via strong and long-range anisotropic interactions. These...
Frustrated Coulomb explosion of helium nanodroplets
Interatomic Coulombic Decay (ICD) is an efficient energy transfer between atoms and molecules. Via ICD, the excess energy of a donor species is transferred to a neighboring acceptor systems which is thus ionized. ICD is a general mechanism, observed in many systems and have a central role in radiation damage as well as in spectroscopical...
Experimental evidence for long-range electron transfer in alkali
clusters interacting with fullerene-doped helium nanodroplets was
reported by the Scheier group. Such reactions are hindered by the very
different propensities of the two reaction partners towards
solubility, alkalis being heliophobic while fullerenes are
heliophilic.
In this contribution, we present a preliminary...
We explore the possibility of electro-association of two ultracold dipolar molecules into a long-range tetramer state, called a "field linked state". These particular states have been predicted in 2003 [1] in a static electric field and more recently in a microwave [2]. Such states have been confirmed by a recent experiment [3] in the resonances of ultracold molecular scattering.
We discuss...
