Analysis of the magnetic coupling in binuclear complexes. I. Physics of the coupling

Accurate estimates of the magnetic coupling in binuclear complexes can be obtained from ab initio configuration interaction ~CI! calculations using the difference dedicated CI technique. The present paper shows that the same technique also provides a way to analyze the various physical contributions to the coupling and performs numerical analysis of their respective roles on four binuclear complexes of Cu (d9) ions. The bare valence-only description ~including direct and kinetic exchange! does not result in meaningful values. The spin-polarization phenomenon cannot be neglected, its sign and amplitude depend on the system. The two leading dynamical correlation effects have an antiferromagnetic character. The first one goes through the dynamical polarization of the environment in the ionic valence bond forms ~i.e., the M1¯M2 structures!. The second one is due to the double excitations involving simultaneously single excitations between the bridging ligand and the magnetic orbitals and single excitations of the environment. This dispersive effect results in an increase of the effective hopping integral between the magnetic orbitals. Moreover, it is demonstrated to be responsible for the previously observed larger metal-ligand delocalization occurring in natural orbitals with respect to the Hartree–Fock one

The Massive Progenitor of the Possible Type II-Linear Supernova 2009hd in Messier 66

We present observations of SN2009hd in the nearby galaxy M66. This SN is one of the closest to us in recent years but heavily obscured by dust, rendering it unusually faint in the optical, given its proximity. We find that the observed properties of SN2009hd support its classification as a possible Type II-L SN, a relatively rare subclass of CC-SNe. High-precision relative astrometry has been employed to attempt to identify a SN progenitor candidate, based on a pixel-by-pixel comparison between HST F555W and F814W images of the SN site prior to explosion and at late times. A progenitor candidate is identified in the F814W images only; this object is undetected in F555W. Significant uncertainty exists in the astrometry, such that we cannot definitively identify this object as the SN progenitor. Via insertion of artificial stars into the pre-SN HST images, we are able to constrain the progenitor's properties to those of a possible supergiant, with M(F555W)0>-7.6 mag and (V-I) 0>0.99 mag. The magnitude and color limits are consistent with a luminous RSG; however, they also allow for the possibility that the star could have been more yellow than red. From a comparison with theoretical massive-star evolutionary tracks, which include rotation and pulsationally enhanced mass loss, we can place a conservative upper limit on the initial mass for the progenitor of <20 M_sun. If the actual mass of the progenitor is near the upper range allowed by our derived mass limit, then it would be consistent with that for the identified progenitors of the SNII-L 2009kr and the high-luminosity SNII-P 2008cn. The progenitors of these three SNe may possibly bridge the gap between lower-mass RSG that explode as SNeII-P and LBV, or more extreme RSG, from which the more exotic SNeII-n may arise. Very late-time imaging of the SN2009hd site may provide us with more clues regarding the true nature of its progenitor.Comment: 19 pages, 9 figures, 3 tables, accepted for publication in Ap

Tracing the volatilomic fingerprint of the most popular Italian fortified wines

The aim of the current study was to provide a useful platform to identify characteristic molecular markers related to the authenticity of Italian fortified wines. For this purpose, the volatilomic fingerprint of the most popular Italian fortified wines was established using headspace solid-phase microextraction combined with gas chromatography–mass spectrometry (HS-SPME/GC-MS). Several volatile organic compounds (VOCs), belonging with distinct chemical groups, were identified, ten of which are common to all the analyzed fortified Italian wines. Terpenoids were the most abundant chemical group in Campari bitter wines due to limonene’s high contribution to the total volatilomic fingerprint, whereas for Marsala wines, alcohols and esters were the most predominant chemical groups. The fortified Italian wines VOCs network demonstrated that the furanic compounds 2-furfural, ethyl furoate, and 5-methyl-2-furfural, constitute potential molecular markers of Marsala wines, while the terpenoids nerol, α-terpeniol, limonene, and menthone isomers, are characteristic of Vermouth wines. In addition, butanediol was detected only in Barolo wines, and β-phellandrene and β-myrcene only in Campari wines. The obtained data reveal an adequate tool to establish the authenticity and genuineness of Italian fortified wines, and at the same time constitute a valuable contribution to identify potential cases of fraud or adulteration to which they are subject, due to the high commercial value associated with these wines. In addition, they contribute to the deepening of scientific knowledge that supports its valorization and guarantee of quality and safety for consumers.This work was funded by FCT—Fundação para a Ciência e a Tecnologia through the CQM Base Fund—UIDB/00674/2020, and Programmatic Fund—UIDP/00674/2020, and by ARDITI— Agência Regional para o Desenvolvimento da Investigação Tecnologia e Inovação, through the project M1420-01-0145-FEDER-000005—Centro de Química da Madeira—CQM+ (Madeira 14-20 Program). The authors also acknowledge the financial support from Fundação para a Ciência e Tecnologia and Madeira 14-2020 program to the Portuguese Mass Spectrometry Network through PROEQUI-PRAM program, M14-20 M1420-01-0145-FEDER-000008. The international collaboration was supported by the Università degli Studi del Piemonte Orientale “A. Avogadro” as a part of the “FREE MOVER PER PROGETTI–a.a. 2021/2022” Project (FlavChem—the Flavor Chemistry of Fortified Wines).info:eu-repo/semantics/publishedVersio

Observations of SN2011fe with INTEGRAL

SN2011fe was detected by the Palomar Transient Factory on August 24th 2011 in M101 few hours after the explosion. From the early spectra it was immediately realized that it was a Type Ia supernova thus making this event the brightest one discovered in the last twenty years. In this paper the observations performed with the instruments on board of INTEGRAL (SPI, IBIS/ISGRI, JEM-X and OMC) before and after the maximum of the optical light as well as the interpretation in terms of the existing models of $\gamma$--ray emission from such kind of supernovae are reported. All INTEGRAL high-energy have only been able to provide upper limits to the expected emission due to the decay of $^{56}$Ni. These bounds allow to reject explosions involving a massive white dwarf in the sub--Chandrasekhar scenario. On the other hand, the optical light curve obtained with the OMC camera suggests that the event was produced by a delayed detonation of a CO white dwarf that produced $\sim 0.5$ M$\odot$ of $^{56}$Ni. In this particular case, INTEGRAL would have only been able to detect the early $\gamma$--ray emission if the supernova had occurred at a distance of 2 -3 Mpc, although the brightest event could be visible up to distances larger by a factor two.Comment: Proceedings of "An INTEGRAL view of the high-energy sky (the first 10 years)" the 9th INTEGRAL Workshop, October 15-19, 2012, Paris, France, in Proceedings of Science (INTEGRAL 2012), Eds. A. Goldwurm, F. Lebrun and C. Winkler, http://pos.sissa.it/cgi-bin/reader/conf.cgi?confid=176, id number PoS (INTEGRAL 2012) 103 (2013

Observation of SN2011fe with INTEGRAL. I. Pre--maximum phase

SN2011fe was detected by the Palomar Transient Factory on August 24th 2011 in M101 a few hours after the explosion. From the early optical spectra it was immediately realized that it was a Type Ia supernova thus making this event the brightest one discovered in the last twenty years. The distance of the event offered the rare opportunity to perform a detailed observation with the instruments on board of INTEGRAL to detect the gamma-ray emission expected from the decay chains of $^{56}$Ni. The observations were performed in two runs, one before and around the optical maximum, aimed to detect the early emission from the decay of $^{56}$Ni and another after this maximum aimed to detect the emission of $^{56}$Co. The observations performed with the instruments on board of INTEGRAL (SPI, IBIS/ISGRI, JEMX and OMC) have been analyzed and compared with the existing models of gamma-ray emission from such kind of supernovae. In this paper, the analysis of the gamma-ray emission has been restricted to the first epoch. Both, SPI and IBIS/ISGRI, only provide upper-limits to the expected emission due to the decay of $^{56}$Ni. These upper-limits on the gamma-ray flux are of 7.1 $\times$ 10$^{-5}$ ph/s/cm$^2$ for the 158 keV line and of 2.3 $\times$ 10$^{-4}$ ph/s/cm$^2$ for the 812 keV line. These bounds allow to reject at the $2\sigma$ level explosions involving a massive white dwarf, $\sim 1$ M$\odot$ in the sub--Chandrasekhar scenario and specifically all models that would have substantial amounts of radioactive $^{56}$Ni in the outer layers of the exploding star responsible of the SN2011fe event. The optical light curve obtained with the OMC camera also suggests that SN2011fe was the outcome of the explosion, possibly a delayed detonation although other models are possible, of a CO white dwarf that synthesized $\sim 0.55$ M$_\odot$ of $^{56}$Ni. For this specific model.Comment: Accepted for publication in A&A. 10 pages, 10 figure

Gemini Planet Imager Observational Calibrations VI: Photometric and Spectroscopic Calibration for the Integral Field Spectrograph

The Gemini Planet Imager (GPI) is a new facility instrument for the Gemini Observatory designed to provide direct detection and characterization of planets and debris disks around stars in the solar neighborhood. In addition to its extreme adaptive optics and corona graphic systems which give access to high angular resolution and high-contrast imaging capabilities, GPI contains an integral field spectrograph providing low resolution spectroscopy across five bands between 0.95 and 2.5 $\mu$m. This paper describes the sequence of processing steps required for the spectro-photometric calibration of GPI science data, and the necessary calibration files. Based on calibration observations of the white dwarf HD 8049B we estimate that the systematic error in spectra extracted from GPI observations is less than 5%. The flux ratio of the occulted star and fiducial satellite spots within coronagraphic GPI observations, required to estimate the magnitude difference between a target and any resolved companions, was measured in the $H$-band to be $\Delta m = 9.23\pm0.06$ in laboratory measurements and $\Delta m = 9.39\pm 0.11$ using on-sky observations. Laboratory measurements for the $Y$, $J$, $K1$ and $K2$ filters are also presented. The total throughput of GPI, Gemini South and the atmosphere of the Earth was also measured in each photometric passband, with a typical throughput in $H$-band of 18% in the non-coronagraphic mode, with some variation observed over the six-month period for which observations were available. We also report ongoing development and improvement of the data cube extraction algorithm.Comment: 15 pages, 6 figures. Proceedings of the SPIE, 9147-30