原子物理
$^{229}$Th is a promising candidate for developing a nuclear optical clock and searching the new physics beyond the standard model. Accurate knowledge of the nuclear properties of $^{229}$Th is very important. In this work, we calculate…
Determination of nuclear moments for many nuclei relies on the computation of hyperfine constants, with theoretical uncertainties directly affecting the resulting uncertainties of the nuclear moments. In this work we improve the precision…
We present an experimental and theoretical study of the absorption and emission spectra of Yb atoms in a solid Ne matrix at a resolution of 0.025 nm. Five absorption bands were identified as due to transitions from the $4f^{14}5d^06s^2\…
Relativistic calculations of the electronic structure of the superheavy element of the eighth period $-$ eka-francium ($Z=119$) and its homologues, which form the group of alkali metals, are performed in the framework of the…
We present experimental data on the non-adiabatic strong field ionization of atomic hydrogen using elliptically polarized femtosecond laser pulses at a central wavelength of 390 nm. Our measured results are in very good agreement with a…
The energy dependence of the rates of the reactions between He$^+$ and ammonia (NY$_3$, Y= {H,D}), forming NY$_2^+$, Y and He as well as NY$^+$, Y$_2$ and He, and the corresponding product branching ratios have been measured at low…
The effect of nuclear polarisation on the non-linearities of King plot for isotope shift in Ca$^+$, Sr$^+$ and Yb$^+$ ions is studied. These ions are currently used in search for the manifestation of new interaction via non-linearities of…
The Autler-Townes effect due to near resonance transition between 4s-4p states in potassium atoms is mapped out in the photo-electron-momentum distribution and manifests itself as a splitting in the photo-electron kinetic energy spectra.…
We present a novel binding mechanism where a neutral Rydberg atom and an atomic ion form a molecular bound state at large internuclear distance. The binding mechanism is based on Stark shifts and level crossings which are induced in the…
The reaction between He$^+$ and CH$_3$F forming predominantly CH$_2^+$ and CHF$^+$ has been studied at collision energies $E_{\rm coll}$ between 0 and $k_{\rm B}\cdot 10$~K in a merged-beam apparatus. To avoid heating of the ions by stray…
High-resolution measurements of angular scattering distributions provide a sensitive test for theoretical descriptions of collision processes. Crossed beam experiments employing a decelerator and velocity map imaging have proven successful…
Understanding ultracold collisions involving molecules is of fundamental importance for current experiments, where inelastic collisions typically limit the lifetime of molecular ensembles in optical traps. Here we present a broad study of…
We report the experimental observation of superradiant emission emanating from an elongated dense ensemble of laser cooled two-level atoms, with a radial extent smaller than the transition wavelength. In the presence of a strong driving…
We present a permanent magnet arrangement that can achieve a tuneable axial magnetic field from 1.80(8)-2.67(2) kG along the z-axis, where (x,y) = (0,0), with a rms field variation of less than 1% over a length of 25 mm. The instrument…
We use double-resonant two-photon laser spectroscopy to measure the dynamic scalar polarizability of the rubidium 5$D_{3/2}$ level, $\alpha^{S}_{5D_{3/2}}$, at a wavelength of $\lambda=1064$~nm. Since $\lambda$ is shorter than the…
We demonstrate the direct loading of a D$_2$ MOT of potassium-39 atoms from a cryogenic buffer gas beam source. We load $10^8$ atoms in a 10 ms pulse, with no degradation in performance up to a 10 Hz repetition rate. Observed densities…
We present a compact, two-stage atomic beam source that produces a continuous, narrow, collimated and high-flux beam of rubidium atoms with sub-Doppler temperatures in three dimensions, which features very low emission of near-resonance…
We demonstrate for the first time the two-color cooling and trapping of alkaline-earth atoms in a grating magneto-optical trap (gMOT). The trap is formed by a single incident laser beam together with four secondary beams that are generated…
We report on the observation of time-resolved quantum beats in the helium fluorescence from the transition 1s3p -> 1s2s, where the initial state is excited by XUV free-electron laser radiation. The quantum beats originate from the Zeeman…
Molecules containing superheavy atoms can be artificially created to serve as sensitive probes for study of symmetry-violating phenomena. Here, we provide a detailed theoretical study for diatomic molecules containing the superheavy…