44 research outputs found
Photoelectron spectroscopy and dissociative photoionization of fulminic acid, HCNO
We report a joint experimental and computational study of the photoelectron spectroscopy and the dissociative photoionization of fulminic acid, HCNO. The molecule is of interest to astrochemistry and astrobiology as a potential precursor of prebiotic molecules. Synchrotron radiation was used as the photon source. Dispersive photoelectron spectra were recorded from 10~eV to 22~eV, covering four band systems in the HCNO cation and an ionization energy of 10.83~eV was determined. Transitions into the Renner-Teller distorted state of the cation were simulated using wavepacket dynamics based on a vibronic coupling Hamiltonian. Very good agreement between experiment and theory is obtained. While the first excited state of the cation shows only a broad and unstructured spectrum, the next two higher states exhibit a well-resolved vibrational progression. Transitions into the excited electronic states of \cation{HCNO}{+} were not simulated, due to the large number of electronic states that contribute to these transitions. Nevertheless, a qualitative assignment is given, based on the character of the orbitals involved in the transitions. The dissociative photoionization was investigated by photoelectron-photoion coincidence spectroscopy. The breakdown diagram shows evidence for isomerization from \cation{HCNO}{+} to \cation{HNCO}{+} on the cationic potential energy surface. Zero Kelvin appearance energies for the daughter ions \cation{HCO}{+} and \cation{NCO}{+} have been derived
Age and gender differences in narcissism: A comprehensive study across eight measures and over 250,000 participants
Age and gender differences in narcissism have been studied often. However, considering the rich history of narcissism research accompanied by its diverging conceptualizations, little is known about age and gender differences across various narcissism measures. The present study investigated age and gender differences and their interactions across eight widely used narcissism instruments (i.e., Narcissistic Personality Inventory, Hypersensitive Narcissism Scale, Dirty Dozen, Psychological Entitlement Scale, Narcissistic Personality Disorder Symptoms from the Diagnostic and Statistical Manual of Mental Disorders, Version IV, Narcissistic Admiration and Rivalry Questionnaire-Short Form, Single-Item Narcissism Scale, and brief version of the Pathological Narcissism Inventory). The findings of Study 1 (N = 5,736) revealed heterogeneity in how strongly the measures are correlated. Some instruments loaded clearly on one of the three factors proposed by previous research (i.e., Neuroticism, Extraversion, Antagonism), while others cross-loaded across factors and in distinct ways. Cross-sectional analyses using each measure and meta-analytic results across all measures (Study 2) with a total sample of 270,029 participants suggest consistent linear age effects (random effects meta-analytic effect of r = -.104), with narcissism being highest in young adulthood. Consistent gender differences also emerged (random effects meta-analytic effect was -.079), such that men scored higher in narcissism than women. Quadratic age effects and Age × Gender effects were generally very small and inconsistent. We conclude that despite the various conceptualizations of narcissism, age and gender differences are generalizable across the eight measures used in the present study. However, their size varied based on the instrument used. We discuss the sources of this heterogeneity and the potential mechanisms for age and gender differences
Spektroskopie der Fulminsäure HCNO mit VUV- und weicher Röntgenstrahlung
Die Fulminsäure HCNO wurde zum ersten Mal im Jahre 1800 synthetisiert und wurde seitdem immer wieder verwendet, um neue chemische Konzepte und Theorien zu entwickeln. Durch die erstmalige Entdeckung der Fulminsäure im Weltall im Jahr 2009 ist die Fulminsäure heutzutage vor allem im Bereich der Astrochemie interessant. In dieser Doktorarbeit haben wir die Interaktion von Fulminsäure mit interstellar Strahlung, genauer mit VUV- sowie weicher Röntgenstrahlung untersucht. In Zuge der Messung mit VUV-Strahlung konnten wir das Photoelektronenspektrum von HCNO mit hoher Auflösung aufnehmen und den Renner-Teller verzerrten Grundzustand des Kations mit Hilfe von Wellenpaketdynamiksimulationen beschreiben. Außerdem konnten wir den Mechanismus der dissoziativen Photoionisation bis zu einer Bindungsenergie von 15.3 eV aufklären. Mit weicher Röntgenstrahlung ist es möglich die 1s Elektronen des HCNO zu ionisieren oder anzuregen. Der erzeugte Zustand zerfällt anschließend durch einen Auger-Meitner Prozess, bei dem ein Auger-Elektron erzeugt wird. Im Zuge der Auger-Elektronenspektroskopie haben wir die kinetische Energie dieser Elektronen gemessen und konnten mittels quantenchemischer Rechnung die beobachten Signale analysieren. Wir untersuchten außerdem, wie das durch den Auger-Meitner Prozess erzeugte Ion zerfällt. Hier konnten wir eine Selektivität des Zerfalls beobachten, je nachdem welches der 1s Elektronen im ersten Schritt angeregt oder ionisiert wurde. Diese Beobachtung konnten wir durch ein einfaches thermodynamisches Argument erklären. Diese Arbeit gibt also ein vollständiges Bild über die Interaktion von HCNO mit ionisierender Strahlung. Die erhaltenen Daten könnten für die Beschreibung von HCNO im interstellaren Raum Bedeutung haben.Fulminic acid, HCNO, was first synthesized in the year 1800 and has since then been used numerous times to develop new chemical theories and concepts. Nowadays, research on HCNO is mainly motivated due to its detection in interstellar space in the year 2009. In this thesis, we investigated the interaction of fulminic acid with VUV- and soft X-ray radiation, i.e., radiation that is also present in the interstellar medium. In our study using VUV radiation, we were able to record the photoelectron spectrum of HCNO with high resolution and we were able to simulate the Renner-Teller distorted ground state of the cation using simulation of wavepacket dynamics. We also elucidated the mechanism of the dissociative photoionisation up to 15.3 eV binding energy. Using soft X-ray radiation enables us to ionise or excite the 1s electrons of HCNO. The created state can decay via an Auger-Meitner process, which produces an Auger electron. We measured the kinetic energy of these auger electron and were able to analyse the observed signals using quantum chemical calculations. We also investigated how the ion fragments after the Auger-Meitner process. We observed a site-selectivity, where the initial ionisation/excitation site influenced the product distribution. We were able to explain this observation with a simple thermodynamic argument. This thesis provides a comprehensive description of the interaction of HCNO with ionising radiation. The obtained data may be valuable for the description of the behaviour of HCNO in interstellar space
Distinguishing Subgroups of Narcissists with Latent Class Analysis
This study investigated grandiose narcissism from a categorical perspective. We tested whether subgroups of narcissists can be distinguished that differ in their expressions of more agentic (narcissistic admiration, ADM) and more antagonistic (narcissistic rivalry, RIV) pathways of narcissism. We analysed three German samples (total N=2211; M-age=26; 70% female) and one US sample (N=971; M-age=35; 74% female) using latent class analysis. Four subgroups of narcissists were consistently identified across samples from Germany and the United States: low narcissists, moderate narcissists primarily characterized by agentic aspects (ADM), moderate narcissists characterized by both agentic and antagonistic aspects (ADM+ RIV), and high narcissists. The subgroups were systematically related to a number of personality traits (e.g. Machiavellianism, impulsivity) and adjustment indicators (e.g. self-esteem, empathy). Members in the moderate narcissists-ADM subgroup showed the most adaptive characteristics while members in the moderate narcissists-ADM+RIV subgroup showed the most maladaptive characteristics. Investigating grandiose narcissism-a primarily quantitative trait-from a categorical perspective can yield valuable insights that would otherwise be overlooked. In addition, our results underline the utility of a self-regulatory process approach to grandiose narcissism that distinguishes between agentic and antagonistic dynamics. Copyright (C) 2016 European Association of Personality PsychologyGerman Research Foundation (DFG) [BA 3731/6-1
Decomposition of Picolyl Radicals at High Temperature: A Mass Selective Threshold Photoelectron Spectroscopy Study
The reaction products of the picolyl radicals at high temperature were characterized by mass‐selective threshold photoelectron spectroscopy in the gas phase. Aminomethylpyridines were pyrolyzed to initially produce picolyl radicals (m /z =92). At higher temperatures further thermal reaction products are generated in the pyrolysis reactor. All compounds were identified by mass‐selected threshold photoelectron spectroscopy and several hitherto unexplored reactive molecules were characterized. The mechanism for several dissociation pathways was outlined in computations. The spectrum of m /z =91, resulting from hydrogen loss of picolyl, shows four isomers, two ethynyl pyrroles with adiabatic ionization energies (IE) of 7.99 eV (2‐ethynyl‐1H ‐pyrrole) and 8.12 eV (3‐ethynyl‐1H ‐pyrrole), and two cyclopentadiene carbonitriles with IE′s of 9.14 eV (cyclopenta‐1,3‐diene‐1‐carbonitrile) and 9.25 eV (cyclopenta‐1,4‐diene‐1‐carbonitrile). A second consecutive hydrogen loss forms the cyanocyclopentadienyl radical with IE′s of 9.07 eV (T) and 9.21 eV (S). This compound dissociates further to acetylene and the cyanopropynyl radical (IE=9.35 eV). Furthermore, the cyclopentadienyl radical, penta‐1,3‐diyne, cyclopentadiene and propargyl were identified in the spectra. Computations indicate that dissociation of picolyl proceeds initially via a resonance‐stabilized seven‐membered ring
X-ray induced fragmentation of fulminic acid, HCNO
Financial support by the Deutsche Forschungsgemeinschaft, Contract No. FI 575/13-2, is gratefully acknowledged. This work was performed on the PLEIADES beamline under Proposal No. 20210814. We acknowledge SOLEIL for provision of synchrotron radiation facilities and thank the PLEIADES beamline team for their assistance
Photoelectron Photoion Coincidence Spectroscopy of NCl and NCl
We investigate NCl and the NCl radical by photoelectron-photoion coincidence spectroscopy using synchrotron radiation. The mass selected threshold photoelectron spectrum (ms-TPES) of NCl is broad and unstructured due to the large geometry change. An ionization energy of 9.7±0.1 eV is estimated from the spectrum and supported by computations. NCl2 is generated by photolysis at 213 nm from NCl and its ms-TPES shows an extended vibrational progression with a 90 meV spacing that is assigned to the symmetric N−Cl stretching mode in the cation. An adiabatic ionization energy of 9.94 ± 0.02 eV is determined
Ammonia Borane, NHBH: A Threshold Photoelectron-Photoion Coincidence Study of a Potential Hydrogen-Storage Material
We have investigated the photoionization of ammonia borane (AB) and determined adiabatic ionization energy to be 9.26±0.03 eV for the X E←X A transition. Although the threshold photoelectron spectrum appears at first glance to be similar to the one of the isosteric ethane, the electronic situation differs markedly, due to different orbital energies. In addition, an appearance energy AE-(NHBH, NHBH)= 10.00±0.03 eV has been determined, corresponding to the loss of a hydrogen atom at the BH-site. From the data, a 0 K bond dissociation energy for the B−H bond in the cation of 71.5±3 kJ mol was derived, whereas the one in the neutral compound has been estimated to be 419±10 kJ mol