Intermolecular interaction plays a crucial role in electron solvation in the condensed phase. Here, we present a femtosecond time-resolved and angle-resolved 2-photon photoemission (2PPE) study on the dynamics of electron solvation in a 2-dimensional ammonia film on a metal substrate. While the weakly chemisorbed first monolayer (ML) supports delocalized image-potential (IP) states that resembl...

Most of this book discusses Fermi gases composed of alkali atoms. Since the first realization of a degenerate K Fermi gas in 1999, Li has been the only other fermionic atom to be cooled below the Fermi temperature. In this contribution we will discuss our recent results on cooling fermionic He below the Fermi temperature. This has not been performed with ground state He, but with He in the meta...

The ionization rate of interstellar material by cosmic rays has been a major source of controversy, with different estimates varying by three orders of magnitude. Observational constraints of this rate have all depended on analyzing the chemistry of various molecules that are produced following cosmic-ray ionization, and in many cases these analyses contain significant uncertainties. Even in th...

– We have studied photoassociation of metastable 2S1 helium atoms near the 2 S1-2 P2asymptote by both ion detection in a magneto-optical trap and trap-loss measurements in a magnetic trap. A detailed comparison between the results of the two experiments gives insight into the mechanism of the Penning ionization process. We have identified four series of resonances corresponding to vibrational m...

In a dc-magnetron discharge with argon feed gas, densities of copper atoms in the ground state Cu(S1/2) and metastable state Cu*(D5/2) were measured by resonance absorption technique, using a commercial hollow cathode lamp as light source. The operating conditions were 0.3 14 μbar argon pressure and 10 200 W magnetron discharge power. The deposition rate of copper in a substrate positioned at 1...

We report a Monte Carlo study of the hysteretic behavior of the site-diluted Ising antiferromagnet on a simple-cubic lattice. States found by reducing the magnetic field from an initial value in the paramagnetic phase show no long-range antiferromagnetic order, whereas states found by increasing the magnetic field from an initially ordered state do show long-range order until the field is incre...

Metal atoms have proved to be sensitive probes of the properties of superfluid helium nanodroplets. To date, all experiments on the doping of helium droplets have concentrated on the attachment of metal atoms in their ground electronic states. Here we report the first examples of metal atoms in excited states becoming attached to helium nanodroplets. The atoms in question are aluminum, and they...

The superconducting state in one-dimensional nanosystems is very delicate. While fluctuations of the phase of the superconducting wave function lead to the spontaneous decay of persistent supercurrents in thin superconducting wires and nanocircuits, discrete phase-slip fluctuations can also lead to more exotic phenomena, such as the appearance of metastable superconducting states in current-bea...

Epigenetic mutations confer heritable changes in gene expression that are not due to changes in the underlying sequence of the DNA. We identified a spontaneous rice mutant, Epi-d1, that shows a metastable dwarf phenotype. The phenotype is mitotically and meiotically inheritable and corresponds to the metastable epigenetic silencing of the DWARF1 (D1) gene. The silenced state is correlated with ...

In this work we report the observation of two different EL2 metastable states in GaAs and the effect of the optical/thermal history of the sample on the behavior of the photoquenching kinetics. In one thermal/optical preparation, the photoquenching curve presented two time constants that have already been interpreted as an indication of two different metastable states. With another preparation,...