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 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

Politik mit dem Einkaufswagen : Unternehmen und Konsumenten als Bürger in der globalen Mediengesellschaft

Forschungsprojekt gefördert durch die DFGEine gegenseitige Durchdringung von Zivilgesellschaft und Markt manifestiert sich in der Politisierung des Konsums und der Selbstinszenierung von Unternehmen als sozial verantwortliche Bürger. Dies wirft grundlegende Fragen zur Neubestimmung von Bürgerschaftskonzepten und zur Erweiterung des Handlungsrepertoires von Protestakteuren in spätmodernen Konsumgesellschaften auf. Dabei fungieren (neue) Medien sowohl als Vermittler unternehmerischen Engagements als auch als Plattform für die Ausbildung neuer Protestformen. Der Band liefert einen Beitrag zur aktuellen Diskussion und versammelt Perspektiven von Wissenschaftlern und Praktikern

Gas phase electronic spectroscopy of ionic carbon chains, rings, fullerenes and analogues

Low temperature gas phase electronic spectra of ionic carbon chains, rings, fullerenes and analogues are presented. These data were obtained through action spectroscopy experiments using a cryogenic radiofrequency ion trapping apparatus. Action spectra of C2n+ (n = 4−14) monocyclic carbon ring cations were recorded by helium tagging. A linear shift of the origin band wavelength of the lowest energy electronic transition of this series with increasing ring size was observed. The potential relevance of these cyclic structures to astrochemical environments is discussed. Higher energy electronic transitions of C20+ were also recorded using a two colour fragmentation approach to obtain data on the bare ion. Theoretical calculations were carried out to support the assignment of a C5+ electronic transition observed in the visible. It was found that DFT is not appropriate to calculate the electronic structure of this small open-shell linear carbon cation. CASPT/ccpvdz and NEVPT2/ccpvtz calculations were used to optimise the electronic structure and calculate the electronic transitions. CCSD(T) single point energy calculations support the identification of the lowest energy geometry. The electronic spectrum of C60+ synthesised in a laser vaporisation source is presented and compared with that of C60+ generated from a commercial sample by electron impact. The source conditions were optimised for C60+ in order to synthesise metallo fullerenes of astrochemical interest. Mass spectra of first attempts to synthesise Na+@C60 are also presented. Electronic spectra of the endohedral fullerenes H2O@C60+ and D2O@C60+ are presented. These data were obtained by one-photon dissociation of weakly bound helium complexes synthesised in a 3K ion trap. The spectra are compared with the electronic transition of the empty C60+ cage, shown to be responsible for several DIBs. The spectrum of H2O@C60+ is found to be much richer in structure, composed of features assigned to rotational excitation of H2O accompanying the electronic transition of the C60+ cage. Two-colour experiments were used to separate contributions from ortho- and para-H2O@C60+ nuclear spin isomers stored in the trap. The obtained data from measurement on H2O@C60+ were compared with D2O@C60+ providing insight into the nature of the transitions observed in the spectra

Altered physiological, affective, and functional connectivity responses to acute stress in patients with alcohol use disorder

The present study examined physiological and affective responses to stress and functional connectivity in Alcohol Use Disorder

Parent- and Teacher-Rated Effectiveness of Cognitive-Behavioral Therapy for Children and Adolescents Under Usual Care Conditions in a University Outpatient Clinic

Compared to randomized controlled trials, studies examining the effectiveness of cognitive behavioral therapy (CBT) in children and adolescents with mental disorders are rare, and a teacher perspective is scarce. The present study investigated the effectiveness of routine CBT in 519 patients aged 6-18years with mental disorders. Changes in mental health problems were assessed in teacher (Teacher Report Form, TRF) and parent rating (Child Behavior Checklist, CBCL) and were analyzed within the total sample, yielding statistically significant, small to medium effect sizes (teacher rating: d=.74-2.39; parent rating: d=.65-1.18). Changes in a subgroup of patients with elevated symptom scores at treatment start were compared to a historical control group receiving weekly academic tutoring. Net total score effect sizes lay between d=0.98 and d=1.29 for teacher rating (parent rating: d=0.84 to d=1.01). Nevertheless, a substantial number of patients remained in the clinical range. Symptom changes during family- and patient-based CBT interventions did not differ from treatments including additional school-based interventions, as was also the case for the comparison of treatments with and without additional pharmacotherapy