Synthesis and Spectroscopy of Buckminsterfullerene Cation C₆₀⁺ in a Cryogenic Ion Trapping Instrument

The assignment of several diffuse interstellar bands in the near-infrared to C60+ ions present at high abundance in space has renewed interest in the astrochemical importance of fullerenes and analogues. Many of the latter have not been produced in macroscopic quantities, and their spectroscopic properties are not available for comparison with astronomical observations. An apparatus has been constructed that combines laser vaporisation synthesis with spectroscopic characterisation at low temperature in a cryogenic trap. This instrument is used here to record the electronic absorptions of C60+ produced by laser vaporisation of graphite. These are detected by (helium tagged) messenger spectroscopy in a cryogenic trap. By comparison with spectra obtained using a sublimed sample of Buckminsterfullerene, the observed data show that this isomer is the dominant C60+ structure tagged with helium at m/z=724, indicating that the adopted approach can be used to access the spectra of other fullerenes and derivatives of astrochemical interest

Electronic Spectroscopy of Monocyclic Carbon Ring Cations for Astrochemical Consideration

[Image: see text] Gas phase electronic spectra of pure carbon cations generated by laser vaporization of graphite in a supersonic jet and cooled to below 10 K and tagged with helium atoms in a cryogenic trap are presented. The measured C(2n)(+)–He with n from 6 to 14, are believed to be monocyclic ring structures and possess an origin band wavelength that shifts linearly with the number of carbon atoms, as recently demonstrated through N(2) tagging by Buntine et al. (J. Chem. Phys.2021, 155, 21430234879679). The set of data presented here further constrains the spectral characteristics inferred for the bare C(2n)(+) ions to facilitate astronomical searches for them in diffuse clouds by absorption spectroscopy

Electronic spectroscopy of 1-cyanonaphthalene cation for astrochemical consideration

Context. Polycyclic aromatic hydrocarbons (PAHs) are believed to be the carriers of the aromatic infrared bands and have been proposed as candidates to explain other astronomical phenomena such as diffuse interstellar bands (DIBs). The first aromatic structures possessing more than one ring, 1- and 2-cyanonaphthalene (CNN), were recently detected by rotational spectroscopy in the dense molecular cloud TMC-1. Laboratory investigations have indicated that due to fast and efficient relaxation through recurrent fluorescence (RF), CNN+ may be photostable in the harsh conditions of the lower density, more diffuse regions of the interstellar medium (ISM) exposed to ultraviolet (UV) radiation. As a result, it has been suggested that the widely held belief that small PAHs present in these regions are dissociated may need to be revisited. If 1-CNN+ is able to survive in the diffuse ISM it may contribute to the population of 1-CNN observed in TMC-1. To investigate the abundance of 1-CNN+ in diffuse clouds, laboratory spectroscopy is required. The present work concerns the electronic spectroscopy of 1-CNN+ in absorption and the search for its spectroscopic fingerprints in diffuse clouds. Aims. The aim is to obtain laboratory data on the electronic transitions of gas-phase 1-CNN+ under conditions appropriate for comparison with DIBs and assess abundance in diffuse clouds. Methods. Spectroscopic experiments are carried out using a cryogenic ion trapping apparatus in which gas-phase 1-CNN+ is cooled to temperatures below 10 K through buffer gas cooling. Calculations are carried out using time-dependent density-functional theory. Results. Experimental and theoretical data on the D2 ← D0 and D3 ← D0 electronic transitions of 1-CNN+ are reported. The former transition has a calculated oscillator strength of f = 0.075 and possesses a pattern dominated by its origin band. The origin band is located at 7343 Å and has a full width at half maximum of 28 Å. In observational data, this falls in a region polluted by telluric water lines, hindering assessment of its abundance. Conclusions. Space-based observations are required to search for the spectroscopic signatures of 1-CNN+ and evaluate the hypothesis that this small aromatic system, stabilised by RF, may be able to survive in regions of the ISM exposed to UV photons

Isomeric and isotopic effects on the electronic spectrum of C60+-He: consequences for astronomical observation of C60+

Laboratory measurements are reported that enable a more accurate determination of the characteristics of the near-infrared absorptions of C-60(+) below 10 K. These data were obtained by photofragmentation of C-60(+)-He complexes in a cryogenic trap. Asymmetry in the profiles of the observed 9577 and 9632 angstrom absorption bands of C-60(+)-He is caused by the attachment of the weakly bound helium atom to hexagonal or pentagonal faces of C-60(+). The implication is that the FWHM of the bands in the electronic spectrum of C-60(+) below 10 K is 1.4 angstrom. The effect of C-13 isotopes on the C-60(+) electronic spectrum is experimentally evaluated by measurement of C-12(60)+-He, (C1C59+)-C-13-C-12-He, and (C2C58+)-C-13-C-12-He. Data on the 9365 angstrom absorption band indicate a wavelength shift of about 0.3 angstrom between the former and latter. This result is consistent with models used to interpret the vibrational isotope effect in the Raman spectrum of neutral C-60. The influence of C-13 isotopes on the 9348, 9365, 9428, 9577, and 9632 angstrom diffuse interstellar bands is expected to be minor considering other broadening factors that affect astronomical observations. The presented data also provide more accurate relative intensities of the five interstellar bands attributed to C-60(+)

Electronic Spectroscopy of He@C60+ for Astrochemical Consideration

The electronic spectrum of the endohedral fullerene He@C+60 observed by messenger spectroscopy in a cryogenic ion trap is presented. The role played by the messanger tag in the adopted experimental method is evaluated by recording spectra of He@C+60 − Hen with n = 1−4. The results indicate a linear shift of ∼ 0.7 Å in the wavelengths allowing accurate gas phase values to be reported. The presence of the helium inside the cage shifts the absorption bands by 2−3 Å toward shorter wavelengths compared to C+60. The magnitude of this displacement will enable searches for the spectral signatures of this fullerene analogue in interstellar environments by absorption spectroscopy. The implications for potential astronomical detection are discussed

Gas-phase electronic spectroscopy of nuclear spin isomer separated H₂O@C and D₂O@C

Gas-phase electronic spectra of H2O@C60+ and D2O@C60+ are presented. These data were obtained by one-photon dissociation of weakly bound helium complexes synthesised in a 3 K ion trap. Measurements were recorded in the vicinity of the 2Ag,2Bg←X2Au electronic transitions of the C60+ cage. Two-colour hole burning experiments enabled nuclear spin isomer pure data to be obtained. The spectra are rich in structure with many absorptions attributed to internal excitation of the encapsulated molecule accompanying the C60+ electronic transition. The experimental data are complemented with density functional theory calculations using the B3LYP functional and 6-31++G** basis set.</p

Consumption caught in the cash nexus.

During the last thirty years, ‘consumption’ has become a major topic in the study of contemporary culture within anthropology, psychology and sociology. For many authors it has become central to understanding the nature of material culture in the modern world but this paper argues that the concept is, in British writing at least, too concerned with its economic origins in the selling and buying of consumer goods or commodities. It is argued that to understand material culture as determined through the monetary exchange for things - the cash nexus - leads to an inadequate sociological understanding of the social relations with objects. The work of Jean Baudrillard is used both to critique the concept of consumption as it leads to a focus on advertising, choice, money and shopping and to point to a more sociologically adequate approach to material culture that explores objects in a system of models and series, ‘atmosphere’, functionality, biography, interaction and mediation

Genome-Wide Association Study of Non-Alcoholic Fatty Liver Disease using Electronic Health Records

Genome‐wide association studies (GWAS) have identified several risk loci for nonalcoholic fatty liver disease (NAFLD). Previous studies have largely relied on small sample sizes and have assessed quantitative traits. We performed a case‐control GWAS in the UK Biobank using recorded diagnosis of NAFLD based on diagnostic codes recommended in recent consensus guidelines. We performed a GWAS of 4,761 cases of NAFLD and 373,227 healthy controls without evidence of NAFLD. Sensitivity analyses were performed excluding other co‐existing hepatic pathology, adjusting for body mass index (BMI) and adjusting for alcohol intake. A total of 9,723,654 variants were assessed by logistic regression adjusted for age, sex, genetic principal components, and genotyping batch. We performed a GWAS meta‐analysis using available summary association statistics. Six risk loci were identified (P < 5*10(−8)) (apolipoprotein E [APOE], patatin‐like phospholipase domain containing 3 [PNPLA3, transmembrane 6 superfamily member 2 [TM6SF2], glucokinase regulator [GCKR], mitochondrial amidoxime reducing component 1 [MARC1], and tribbles pseudokinase 1 [TRIB1]). All loci retained significance in sensitivity analyses without co‐existent hepatic pathology and after adjustment for BMI. PNPLA3 and TM6SF2 remained significant after adjustment for alcohol (alcohol intake was known in only 158,388 individuals), with others demonstrating consistent direction and magnitude of effect. All six loci were significant on meta‐analysis. Rs429358 (P = 2.17*10(−11)) is a missense variant within the APOE gene determining ϵ4 versus ϵ2/ϵ3 alleles. The ϵ4 allele of APOE offered protection against NAFLD (odds ratio for heterozygotes 0.84 [95% confidence interval 0.78‐0.90] and homozygotes 0.64 [0.50‐0.79]). Conclusion: This GWAS replicates six known NAFLD‐susceptibility loci and confirms that the ϵ4 allele of APOE is associated with protection against NAFLD. The results are consistent with published GWAS using histological and radiological measures of NAFLD, confirming that NAFLD identified through diagnostic codes from consensus guidelines is a valid alternative to more invasive and costly approaches

The consumption of work: representations and interpretations of the meaning of work at a UK university

This paper focuses on representations of the nexus of work, meaning and consumption as experienced by university students. We develop an empirically based argument that the meaning of work is being constructed as an object of consumption on a British university campus. We suggest that this indicates two key changes in representations of the meaning of work. First, there is a significant shift in the social construction of orientations to work towards what we term ‘consumption of work’. Second, we argue that this new social construction is made up of three dimensions: consumption of an idealised image of work, consumption through specific work processes and consumption of self-development opportunities at work. We conclude by suggesting ways in which this argument could be researched further