title: Gas-phase formation of large neutral alkaline-earth metal tryptophan complexes.
abstract: We report on the first observation of isolated large neutral metal amino acid complexes such as Trp(n)Me(k), with Me=Ca, Ba, Sr, cluster combinations covering n=1...33, k=0..2 and masses beyond 6500 u. The cluster beam is generated using UV laser desorption from a mixed powder of alkaline-earth metal salts and tryptophan inside a cluster mixing channel. The particles are detected using VUV photoionization followed by time-of-flight mass spectroscopy. The enhanced stability of metal amino acid clusters over pure amino acid clusters is substantiated in molecular dynamics simulations by determining the gain in binding energy related to the inclusion of the metal atoms.
authors.affiliation: Faculty of Physics, University of Vienna, Vienna, Austria.
authors.forename: Markus
authors.initials: M
authors.lastname: Marksteiner
authors.forename: Philipp
authors.initials: P
authors.lastname: Haslinger
authors.forename: Hendrik
authors.initials: H
authors.lastname: Ulbricht
authors.forename: Michele
authors.initials: M
authors.lastname: Sclafani
authors.forename: Harald
authors.initials: H
authors.lastname: Oberhofer
authors.forename: Christoph
authors.initials: C
authors.lastname: Dellago
authors.forename: Markus
authors.initials: M
authors.lastname: Arndt