55 research outputs found
Normativity without dualism: Connecting the dots between natural and social sciences
The normative phenomenon is ubiquitous in human interactions, emerging in a wide range of fields studied by social science and considered as one of the essential traits of human’s way of life. The modern subjectivist tradition of social science has been based on a model in which elements like self, freedom and reason play the most relevant roles in explaining normativity by connecting beliefs to behaviors by means of motives that are non-reducible to preferences, desires or impulses. In this paper I will discuss normativity in general in order to turn into normativity as it is conceived in social science and then with a focus on normativity based on reasons. I will argue in favor of a naturalistic approach to normativity by means of a defense of a concept of will, which can provide a bridge between social and natural science, rather than giving further reason to sustain a dualistic approach to them. Moreover, I will claim that mental qualities usually alleged to be essential for assigning personality, agency, and moral responsibility, such as rationality, self-consciousness, and freedom, are neither sufficient nor necessary for a naturalistic characterization of moral agents, or for explaining normativity in human evaluative practices
Core excitation in Ozone localized to one of two symmetry-equivalent chemical bonds - molecular alignment through vibronic coupling
Core excitation from terminal oxygen O in O is shown to be an
excitation from a localized core orbital to a localized valence orbital. The
valence orbital is localized to one of the two equivalent chemical bonds. We
experimentally demonstrate this with the Auger Doppler effect which is
observable when O is core-excited to the highly dissociative
O1s7a state. Auger electrons emitted from the atomic oxygen
fragment carry information about the molecular orientation relative to the
electromagnetic field vector at the moment of excitation. The data together
with analytical functions for the electron-peak profiles give clear evidence
that the preferred molecular orientation for excitation only depends on the
orientation of one bond, not on the total molecular orientation. The
localization of the valence orbital "7a" is caused by mixing of the valence
orbital "5b" through vibronic coupling of anti-symmetric stretching mode
with b-symmetry. To the best of our knowledge, it is the first discussion
of the localization of a core excitation of O. This result explains the
success of the widely used assumption of localized core excitation in
adsorbates and large molecules
Photoabsorption and photoionization studies of the amino acid proline in the VUV region
Ionic fragmentation of the sublimated amino acid DL-proline has been studied using time-of-flight mass spectrometry and synchrotron radiation. Total ion yield and mass spectra were recorded in the 13 to 21.6 eV energy range. Partial ion yields have been calculated for the produced fragments and the results analyzed in a comparative way. Mass spectrum of proline previously obtained at 21.21 eV using photons from a discharge lamp (He I), was used as reference in the comparison to the synchrotron radiation based spectra. The loss of the COOH fragment represents the most probable dissociation pathway following the photoionization of DL-proline in the valence region. These are the first results of total and partial ion yields spectra for this molecule in its gas phase in the valence region using time-of-flight spectrometry
Experiences with the narrow gap undulator at MAX-lab
An undulator with short poles (period 24 mm) and extremely narrow gap (magnet gap 7.7 mm) using a squeezable vacuum chamber has been installed and is in operation at the MAX-lab 550 MeV storage ring. The device operates with a vacuum chamber aperture down to 6.2 mm. The behaviour of the storage ring concerning lifetime, emittance, tune shift and closed orbit is well described by conventional models. We present here the design of the device, the influence on the storage ring and the spectral characteristics, as well as comparison with expected theoretical results and an overview of the activities at the beam line
Theoretical and Experimental Study of Valence Photoelectron Spectrum of d,l-Alanine Amino Acid
In this work, the He–I (21.218 eV) photoelectron
spectrum
of d,l-alanine in the gas phase is revisited experimentally
and theoretically. To support the experiment, the high level ab initio
calculations were used to calculate and assign the photoelectron spectra
of the four most stable conformers of gaseous alanine, carefully.
The symmetry adapted cluster/configuration interaction (SAC-CI) method
based on single and double excitation operators (SD-R) and its more
accurate version, termed general-R, was used to separately calculate
the energies and intensities of the ionization bands of the l- and d-alanine conformers. The intensities of ionization
bands were calculated based on the monopole approximation. Also, natural
bonding orbital (NBO) calculations were employed for better spectral
band assignment. The relative electronic energy, Gibbs free energy,
and Boltzmann population ratio of the conformers were calculated at
the experimental temperature (403 K) using several theoretical methods.
The theoretical photoelectron spectrum of alanine was calculated by
summing over the spectra of individual d and l conformers
weighted by different population ratios. Finally, the population ratio
of the four most stable conformers of alanine was estimated from the
experimental photoelectron spectrum using theoretical calculations
for the first time
Theoretical and Experimental Study of Valence Photoelectron Spectrum of d,l-Alanine Amino Acid
In this work, the He–I (21.218 eV) photoelectron
spectrum
of d,l-alanine in the gas phase is revisited experimentally
and theoretically. To support the experiment, the high level ab initio
calculations were used to calculate and assign the photoelectron spectra
of the four most stable conformers of gaseous alanine, carefully.
The symmetry adapted cluster/configuration interaction (SAC-CI) method
based on single and double excitation operators (SD-R) and its more
accurate version, termed general-R, was used to separately calculate
the energies and intensities of the ionization bands of the l- and d-alanine conformers. The intensities of ionization
bands were calculated based on the monopole approximation. Also, natural
bonding orbital (NBO) calculations were employed for better spectral
band assignment. The relative electronic energy, Gibbs free energy,
and Boltzmann population ratio of the conformers were calculated at
the experimental temperature (403 K) using several theoretical methods.
The theoretical photoelectron spectrum of alanine was calculated by
summing over the spectra of individual d and l conformers
weighted by different population ratios. Finally, the population ratio
of the four most stable conformers of alanine was estimated from the
experimental photoelectron spectrum using theoretical calculations
for the first time
Journal of Mathematical Chemistry
Texto completo. Acesso restrito. p. 317-330Concepts of functional analysis, namely, regular points, tangent subspaces, constraint surfaces,
Lagrangian matrix restricted to the tangent subspace of a constraint surface, are presented
in connection with the Hartree-Fock (HF) problem. The energy functional in LCAO
approximation is considered to be a polynomial function of several variables subject to subsidiary
conditions. General HF equations and instability conditions for the unrestricted Hartree-
Fock (UHF) solutions are derived from this standpoint
Femtosecond fragmentation of CS after sulfur 1s ionization: interplay between Auger cascade decay, charge delocalization, and nuclear motion
We present a combined experimental and theoretical study of the fragmentation of molecular CS2 after sulfur 1s Auger cascade decay, consisting of electron–multi-ion coincidence spectra of charged fragments and theoretical simulations combining density functional theory and molecular dynamics. On the experimental side, a procedure for a complete determination of all sets of ions formed is described. For many of the fragmentation channels, we observed a higher charge in one of the sulfur atoms than the other atoms. Based on these observations and the theoretical simulations where the time scale of the nuclear motion and decay is taken into account, we propose that KLL Auger decay after the 1s core hole creation, via 2p double hole states, results in highly charged and strongly repulsive states with one localized core hole. These localized core holes are sufficiently long-lived that some will decay after fragmentation of the molecular ion, thereby efficiently impeding charge exchange between the fragments
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