Large atom number dual-species magneto-optical trap for fermionic 6Li and 40K atoms

We present the design, implementation and characterization of a dual-species magneto-optical trap (MOT) for fermionic 6Li and 40K atoms with large atom numbers. The MOT simultaneously contains 5.2x10^9 6Li-atoms and 8.0x10^9 40K-atoms, which are continuously loaded by a Zeeman slower for 6Li and a 2D-MOT for 40K. The atom sources induce capture rates of 1.2x10^9 6Li-atoms/s and 1.4x10^9 40K-atoms/s. Trap losses due to light-induced interspecies collisions of ~65% were observed and could be minimized to ~10% by using low magnetic field gradients and low light powers in the repumping light of both atomic species. The described system represents the starting point for the production of a large-atom number quantum degenerate Fermi-Fermi mixture

Low-lying, Rydberg states of polycyclic aromatic hydrocarbons (PAHs) and cyclic alkanes

TD-DFT calculations of low-lying, Rydberg states of a series of polycyclic hydrocarbons and cyclic alkanes are presented. Systematic variations in binding energies and photoelectron angular distributions for the first members of the s, p and d Rydberg series are predicted for increasing molecular complexity. Calculated binding energies are found to be in very good agreement with literature values where they exist for comparison. Experimental angle-resolved photoelectron spectroscopy results are presented for coronene, again showing very good agreement with theoretical predictions of binding energies and also for photoelectron angular distributions. The Dyson orbitals for the small "hollow" carbon structures, cubane, adamantane and dodecahedrane, are shown to have close similarities to atomic s, p and d orbitals, similar to the superatom molecular orbitals (SAMOs) reported for fullerenes, indicating that these low-lying, diffuse states are not restricted to π-conjugated molecules. © 2017 the Owner Societies

Slow Molecules Produced by Photodissociation

A simple method to control molecular translation with a chemical reaction is demonstrated. Slow NO molecules have been produced by partially canceling the molecular beam velocity of NO$_2$ with the recoil velocity of the NO photofragment. The NO$_2$ molecules were photodissociated using a UV laser pulse polarized parallel to the molecular beam. The spatial profiles of NO molecules showed two peaks corresponding to decelerated and accelerated molecules, in agreement with theoretical prediction. A significant portion of the decelerated NO molecules stayed around the initial dissociation positions even several hundred nanoseconds after their production.Comment: 17 pages, 4 figure

PROBING THE MOLECULAR DYNAMICS OF A Cu(CD3_3OD) CLUSTER WITH PHOTODETACHMENT-PHOTOIONIZATION SPECTROSCOPY

Author Institution: JILA/Department of Chemistry, University of Colorado, Boulder, CO 80309; Department of Chemistry, Ohio State University, Columbus, OH 43210We report the femtosecond nuclear dynamics of neutral Cu(CD$_3$OD) van der Waals clusters, investigated using photodetachment-photoionization spectroscopy. Photodetachment of Cu(CD$_3$OD) anion with a 150 fs 400 nm laser pulse produces a vibrationally excited neutral complex that undergoes ligand reorientation and dissociation. The time evolving neutral is interrogated by delayed femtosecond resonant two photon ionization. This study shows that the nascent Cu(CD$_3$OD) complex dissociates on prompt (3 ps) and slower timescales (30 ps). The prompt component reflects direct dissociation upon photodetachment, while the slower dissociation arises from the coupling of CD$_3$OD molecular rotation into the Cu-(CD$_3$OD) dissociation coordinate. Theoretical investigations provide insight to the nature of the molecular dynamics which produce the observed dissociation characteristics. Supported by NSF and AFOS