scholarly journals Submersion of rubidium clusters in helium nanodroplets

2021 ◽  
Vol 75 (4) ◽  
Author(s):  
Arne Schiller ◽  
Paul Martini ◽  
Elias Emile Jabbour Al Maalouf ◽  
Paul Scheier
Keyword(s):  
Experimental Studies ◽  
Cluster Ions ◽  
Size Distributions ◽  
Helium Nanodroplets ◽  
Alkali Atoms ◽  
Electron Impact Mass ◽  
Helium Droplet ◽  
Small Clusters ◽  
Sodium And Potassium ◽  
Impact Mass

Abstract Alkali atoms and small clusters are known to reside on the surface of a helium droplet rather than its inside as most other dopant species. A theoretical investigation suggested that alkali clusters (Li–Rb) exceeding a certain critical size can become submerged in the droplet, which was experimentally confirmed for sodium and potassium. Here, we report an analogous experimental study of rubidium cluster submersion by means of electron impact mass spectrometry. We recorded size distributions of Rb cluster ions at various electron energies between 8 and 160 eV. Our data suggest that Rb clusters attached to helium droplets undergo a gradual submersion transition similar to potassium, ultimately leading to the full submersion of clusters larger than $$\sim 100~\hbox {Rb}$$ ∼ 100 Rb atoms. Our findings are consistent with previous theoretical and experimental studies. Graphic abstract

scholarly journals Substituent Effects on EI-MS Fragmentation Patterns of 5-Allyloxy-1-aryl-tetrazoles and 4-Allyl-1-aryl-tetrazole-5-ones; Correlation with UV-Induced Fragmentation Channels

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3282
Author(s):  
Alina Secrieru ◽  
Rabah Oumeddour ◽  
Maria L. S. Cristiano
Keyword(s):  
Theoretical Calculations ◽  
Substituent Effects ◽  
Radical Cations ◽  
Electronic Effects ◽  
Diverse Range ◽  
The Matrix ◽  
Electron Impact Mass ◽  
Fragmentation Patterns ◽  
Tetrazole Derivatives ◽  
Impact Mass

1,4- and 1,5-disubstituted tetrazoles possess enriched structures and versatile chemistry, representing a challenge for chemists. In the present work, we unravel the fragmentation patterns of a chemically diverse range of 5-allyloxy-1-aryl-tetrazoles and 4-allyl-1-aryl-tetrazolole-5-ones when subjected to electron impact mass spectrometry (EI-MS) and investigate the correlation with the UV-induced fragmentation channels of the matrix-isolated tetrazole derivatives. Our results indicate that the fragmentation pathways of the selected tetrazoles in EI-MS are highly influenced by the electronic effects induced by substitution. Multiple pathways can be envisaged to explain the mechanisms of fragmentation, frequently awarding common final species, namely arylisocyanate, arylazide, arylnitrene, isocyanic acid and hydrogen azide radical cations, as well as allyl/aryl cations. The identified fragments are consistent with those found in previous investigations concerning the photochemical stability of the same class of molecules. This parallelism showcases a similarity in the behaviour of tetrazoles under EI-MS and UV-irradiation in the inert environment of cryogenic matrices of noble gases, providing efficient tools for reactivity predictions, whether for analytical ends or more in-depth studies. Theoretical calculations provide complementary information to articulate predictions of resulting products.

Mammalian exocrine secretions XIX. Chemical characterization of the interdigital secretion of the Black Wildebeest, Connochaetes gnou

2020 ◽  
Vol 75 (9-10) ◽  
pp. 339-351
Author(s):  
Barend V. Burger ◽  
Desmond Slade ◽  
Marlize Z. Bekker ◽  
Aron H. Goitom
Keyword(s):  
Chemical Characterization ◽  
Male And Female ◽  
Black Wildebeest ◽  
Connochaetes Gnou ◽  
Electron Impact Mass ◽  
Males And Females ◽  
Strong Attachment ◽  
Impact Mass ◽  
Acid Esters

AbstractUsing gas chromatography (GC) in conjunction with electron impact mass spectrometry and retention-time comparison, 94 compounds, ranging from 2-methyl-2-propenal to octadecanoic acid, were identified in the interdigital secretions of male and female black wildebeests, Connochaetes gnou (also known as the white-tailed gnu). The constituents of these secretions belong to many different compound classes, including hydrocarbons, alcohols, aromatics and aliphatic carbonyl compounds including carboxylic acids as well as carboxylic acid esters. Relatively small quantitative differences were found between the male and female interdigital secretions. It was concluded that these compounds probably do not play a significant role in territorial marking or in chemical communication between males and females of the species, but they could be involved in preserving the remarkably strong attachment between members of social subgroups in black wildebeest populations.

ISLAND-SIZE DISTRIBUTIONS OF Ag ON Pd(111)

1996 ◽  
Vol 03 (03) ◽  
pp. 1393-1402 ◽  
Author(s):  
R. FISCHER ◽  
TH. FAUSTER ◽  
W. VON DER LINDEN ◽  
V. DOSE
Keyword(s):  
Maximum Entropy Method ◽  
Entropy Method ◽  
Bayesian Probability ◽  
Magic Numbers ◽  
Size Distributions ◽  
Island Size ◽  
Two Phase ◽  
Two Photon ◽  
Small Clusters ◽  
Image State

Island-size distributions of submonolayer Ag films on Pd(111) adsorbed at 90 K and after annealing of the film are recovered from two-photon photoemission spectra of the first image state. The inversion of the ill-conditioned problem with the maximum-entropy method reveals magic numbers in the island-size distributions. Hypothesis testing within the framework of Bayesian probability theory indicates a critical nucleus size i=1. After annealing of the film large islands coexist with small clusters in a two-phase state.

Sign in / Sign up

Export Citation Format

Share Document