Deceleration and electrostatic trapping of OH radicals

A pulsed beam of ground state OH radicals is slowed down using a Stark decelerator and is subsequently loaded into an electrostatic trap. Characterization of the molecular beam production, deceleration and trap loading process is performed via laser induced fluorescence detection inside the quadrupole trap. Depending on details of the trap loading sequence, typically $10^5$ OH ($X^2\Pi_{3/2}, J=3/2$) radicals are trapped at a density of around $10^7$ cm$^{-3}$ and at temperatures in the 50-500 mK range. The 1/e trap lifetime is around 1.0 second.Comment: 4 pages, 3 figure

Loading Stark-decelerated molecules into electrostatic quadrupole traps

Beams of neutral polar molecules in a low-field seeking quantum state can be slowed down using a Stark decelerator, and can subsequently be loaded and confined in electrostatic quadrupole traps. The efficiency of the trap loading process is determined by the ability to couple the decelerated packet of molecules into the trap without loss of molecules and without heating. We discuss the inherent difficulties to obtain ideal trap loading, and describe and compare different trap loading strategies. A new "split-endcap" quadrupole trap design is presented that enables improved trap loading efficiencies. This is experimentally verified by comparing the trapping of OH radicals using the conventional and the new quadrupole trap designs

Direct measurement of the radiative lifetime of vibrationally excited OH radicals

Neutral molecules, isolated in the gas-phase, can be prepared in a long-lived excited state and stored in a trap. The long observation time afforded by the trap can then be exploited to measure the radiative lifetime of this state by monitoring the temporal decay of the population in the trap. This method is demonstrated here and used to benchmark the Einstein $A$-coefficients in the Meinel system of OH. A pulsed beam of vibrationally excited OH radicals is Stark decelerated and loaded into an electrostatic quadrupole trap. The radiative lifetime of the upper $\Lambda$-doublet component of the $X ^2\Pi_{3/2}, v=1, J=3/2$ level is determined as $59.0 \pm 2.0$ ms, in good agreement with the calculated value of $57.7 \pm 1.0$ ms.Comment: 4 pages, 3 figures, submitted to Phys. Rev. Let

Development of a fast laser ablation-inductively coupled plasma-mass spectrometry cell for sub-µm scanning of layered materials

Performance data are reported for a commercially available laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) setup, equipped with a custom-made cell. The low dispersion ablation cell and the connecting tubing achieve a 99% washout of the aerosol in similar to 6 ms, enabling separated pulse responses at frequencies up to 200-300 Hz. In addition, the cell employed supports a post-acquisition methodology for the deconvolution of overlapping ablation positions in scanning mode by an iterative Richardson-Lucy algorithm. This enables correction of the distortion in the scan profile upon traversing layers with dimensions below the physical size of the laser beam. By overlapping the ablation positions of a 1 mu m diameter laser beam, a lateral resolution in the order of 0.3 +/- 0.1 mu m was demonstrated for scanning of mu m-sized layers in high capacitance multi-layer ceramic capacitors

Integrable and superintegrable systems associated with multi-sums of products

We construct and study certain Liouville integrable, superintegrable, and non-commutative integrable systems, which are associated with multi-sums of products.Comment: 26 pages, submitted to Proceedings of the royal society

Strong-coupling effects in the relaxation dynamics of ultracold neutral plasmas

We describe a hybrid molecular dynamics approach for the description of ultracold neutral plasmas, based on an adiabatic treatment of the electron gas and a full molecular dynamics simulation of the ions, which allows us to follow the long-time evolution of the plasma including the effect of the strongly coupled ion motion. The plasma shows a rather complex relaxation behavior, connected with temporal as well as spatial oscillations of the ion temperature. Furthermore, additional laser cooling of the ions during the plasma evolution drastically modifies the expansion dynamics, so that crystallization of the ion component can occur in this nonequilibrium system, leading to lattice-like structures or even long-range order resulting in concentric shells