Continuity of heavy Rydberg behaviour in the ungerade ion-pair states of H 2

Heavy Rydberg behaviour and absolute quantum defects are reported for resonances in the ungerade manifold of H2 above the (1s, 3l) dissociation limit. The continuity of the vibrational progression of the B\u27\u27B-bar state through the crossing with the 3p asymptote is demonstrated and a predominantly diabatic picture of the vibrational motion emerges, indicating that the ion-pair resonances possess little 61Σu+ state character

Conserved synteny at the protein family level reveals genes underlying Shewanella species’ cold tolerance and predicts their novel phenotypes

© The Authors 2009. This article is distributed under the terms of the Creative Commons Attribution Noncommercial License. The definitive version was published in Functional & Integrative Genomics 10 (2010): 97-110, doi:10.1007/s10142-009-0142-y.Bacteria of the genus Shewanella can thrive in different environments and demonstrate significant variability in their metabolic and ecophysiological capabilities including cold and salt tolerance. Genomic characteristics underlying this variability across species are largely unknown. In this study, we address the problem by a comparison of the physiological, metabolic, and genomic characteristics of 19 sequenced Shewanella species. We have employed two novel approaches based on association of a phenotypic trait with the number of the trait-specific protein families (Pfam domains) and on the conservation of synteny (order in the genome) of the trait-related genes. Our first approach is top-down and involves experimental evaluation and quantification of the species’ cold tolerance followed by identification of the correlated Pfam domains and genes with a conserved synteny. The second, a bottom-up approach, predicts novel phenotypes of the species by calculating profiles of each Pfam domain among their genomes and following pair-wise correlation of the profiles and their network clustering. Using the first approach, we find a link between cold and salt tolerance of the species and the presence in the genome of a Na+/H+ antiporter gene cluster. Other cold-tolerance-related genes include peptidases, chemotaxis sensory transducer proteins, a cysteine exporter, and helicases. Using the bottom-up approach, we found several novel phenotypes in the newly sequenced Shewanella species, including degradation of aromatic compounds by an aerobic hybrid pathway in Shewanella woodyi, degradation of ethanolamine by Shewanella benthica, and propanediol degradation by Shewanella putrefaciens CN32 and Shewanella sp. W3-18-1.This research was supported by the U.S. Department of Energy (DOE) Office of Biological and Environmental Research under the Genomics: GTL Program via the Shewanella Federation consortium

Heavy Rydberg and ion-pair states: chemistry, spectroscopy and theory

Recent advances in our knowledge of heavy Rydberg and ion-pair states are critically reviewed, with emphasis placed on the close kinship between the two. Heavy Rydberg states are long-range vibrational states, reaching far beyond ≫102 Å for higher levels. Enhanced chemical reactivity and efficient energy transfer are frequently encountered. Unusual physical properties result from the large dipole moments, including laser-induced reactions and amplified spontaneous emission, and are discussed in the context of the underlying electronic structure. Heavy Rydberg states have a rich spectroscopy which is amenable to quantum defect analysis, as illustrated for a wide range of UV and VUV spectra previously analyzed in terms of Dunham coefficients. The lifetimes of heavy Rydberg states can be long, enabling them to be isolated in cryogenic matrices or as high angular momentum states in the gas phase. Heavy Rydberg and electronic Rydberg states often occupy the same energy region and this, together with the high density of heavy Rydberg vibrational levels, leads to vibronic mixing and numerous perturbations that are a fertile field for analysis by multichannel quantum defect theory and reactive scattering calculations