Frequency-modulation saturation spectroscopy of molecular iodine hyperfine structure near 640 nm with a diode laser source

In a frequency-modulation spectroscopy experiment, using the radiation from a single frequency diode laser, the spectra of molecular iodine hyperfine structure near 640 nm were recorded on the transition $B^3\Pi_{0_u^{+}}-X^1\Sigma^+_{g}$. The frequency reference given by the value of the modulation frequency (12.5 MHz in given experiment) allows determination of the frequency differences between hyperfine components with accuracy better than 0.1 MHz using the fitting procedure in experiment with only one laser.Comment: 3 pages, 3 figure

Inverse semigroup actions as groupoid actions

To an inverse semigroup, we associate an \'etale groupoid such that its actions on topological spaces are equivalent to actions of the inverse semigroup. Both the object and the arrow space of this groupoid are non-Hausdorff. We show that this construction provides an adjoint functor to the functor that maps a groupoid to its inverse semigroup of bisections, where we turn \'etale groupoids into a category using algebraic morphisms. We also discuss how to recover a groupoid from this inverse semigroup.Comment: Corrected a typo in Lemma 2.14 in the published versio

Recent Advances in the Synthesis and Application of SF5-Containing Organic Compounds

It is well known that fluorinated molecules play an important role in daily life. For example, organic molecules bearing either a fluorine atom itself or a short polyfluorinated substituent such as mono-, difluoro-, and trifluoromethyl groups, or pentafluoroethyl and perfluoropropyl groups are already widely used in medicinal and agricultural chemistry. In contrast, molecules with long perfluorinated chains have found vast application in materials science. Among the fluorine-containing moieties, the pentafluorosulfanyl (SF5) substituent occupies a special place.1 The pentafluorosulfanyl group brings unique properties to organic compounds and often improves their biological activities due to the group’s high chemical and metabolic stability, significant lipophilicity, substantial steric effect, unique geometry, and low surface energy. Here we present new routes towards SF5-substituted aliphatic and heterocyclic compounds

Hyperfine magnetic fields at the nuclei of probe ¹¹⁹Sn atoms and exchange interactions in the CaCu₃Mn_3.96Sn_0.04O₁₂ manganite

We have investigated the hyperfine magnetic interactions between the nuclei of probe 119Sn atoms in the CaCu3Mn3.96Sn0.04O12 double manganite by Mössbauer spectroscopy using magnetic measurements. A consistent description of the results obtained in terms of the Weiss molecular field model by taking into account the peculiarities of the local environment of tin atoms has allowed the indirect Cu2+-O-Mn4+ (J CuMn ≈ −51 ± 1 K) and Mn4+-O-Mn4+ (J MnMn ≈ −0.6 ± 0.6 K) exchange interaction integrals to be estimated. Based on the Kanamori-Goodenough-Anderson model, we show that the magnitude and sign of the intrasublattice exchange integral J MnMn correspond to both the electronic configuration of the Mn4+ cations and the geometry of their local crystallographic environment in the compound under study

Pentafluorosulfanyl­di­fluoroacetic Acid: Rebirth of a Promising Building Block

Three novel, easily scalable routes for the synthesis of penta­fluoro­sulfanyl­di­fluoro­acetic acid, SF₅CF₂C­(O)­OH, are described. Reactions of its acid chloride with amines and alcohols led to a small library of 15 amides and five esters, respectively. The reaction of the acid chloride with phenyl­magnesium bromide gave the corresponding aceto­phenone. Penta­fluoro­sulfanyl­difluoro­aceto­nitrile was obtained from penta­fluoro­sulfanyl­di­fluoro­acetamide by dehydration with diphosphorus pentoxide