Wolfgang Ernst

Learn More
In this paper we describe an application of reversed time-correlated single photon counting to the time-resolved spectroscopy of impurity atoms and molecules bound to large quantum clusters. The photo-induced dynamics of Na atoms on the surface of He and clusters have been studied by follow-H 2 ing the time dependence of their emission at selected(More)
Chromium (Cr) atoms embedded into helium nanodroplets (HeN) are ejected from the droplets upon photoexcitation. During ejection they undergo electronic relaxation resulting in bare Cr atoms in various excited states. In a study of the relaxation process we present absorption spectra observed via laser induced fluorescence and beam depletion as well as(More)
We present a series of molecular dynamics simulations on the surface deposition process of initially free silver clusters (Agn) with different sizes (n = 100-2000) and morphologies. During the whole deposition process the morphology of the clusters was studied as a function of the landing conditions. These conditions include variations of the depth and(More)
Using helium cluster-isolation spectroscopy we have prepared and characterized the lowest quartet state (1 4 A 0 2) of the sodium trimer. Upon excitation to the 2 4 E 0 electronic state, laser induced fluorescence excitation and emission spectra have been obtained. With the aid of ab initio calculations, the spectra have been vibronically assigned and new(More)
We investigate the photoinduced relaxation dynamics of Cr atoms embedded into superfluid helium nanodroplets. One- and two-color resonant two-photon ionization (1CR2PI and 2CR2PI, respectively) are applied to study the two strong ground state transitions z(7)P(2,3,4)° ← a(7)S3 and y(7)P(2,3,4)° ← a(7)S3. Upon photoexcitation, Cr* atoms are ejected from the(More)
We report on the formation of mixed alkali-alkaline earth molecules (LiCa) on helium nanodroplets and present a comprehensive experimental and theoretical study of the ground and excited states of LiCa. Resonance enhanced multiphoton ionization time-of-flight (REMPI-TOF) spectroscopy and laser induced fluorescence (LIF) spectroscopy were used for the(More)
Collision times for the coinage metal atoms Cu, Ag and Au in He-droplets are derived from helium density functional theory and molecular dynamics simulations. The strength of the attractive interaction between the metal atoms turns out to be less important than the mass of the propagating metal atoms. Even for small droplets consisting of a few thousand(More)
He-droplet-induced changes of the hyperfine structure constants of alkali-metal atoms are investigated by a combination of relativistically corrected ab initio methods with a simulation of the helium density distribution based on He density functional theory. Starting from an accurate description of the variation of the hyperfine structure constant in the(More)
Structure, shape and composition are the basic parameters responsible for properties of nanoscale materials, distinguishing them from their bulk counterparts. To reveal these in three dimensions at the nanoscale, electron tomography is a powerful tool. Advancing electron tomography to atomic resolution in an aberration-corrected transmission electron(More)