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Trilobites

Trilobites are marine arthropods that appeared in Cambrian Epoch 2 and became extinct at the end of the Permian. In some Paleozoic deposits, they number among the most abundant macrofossils. Trilobites are important for early Paleozoic biostratigraphy, especially Cambrian.

The Cambrian Period

Appearance of metazoans with mineralized skeletons, “explosion” in biotic diversity and disparity, infaunalization of the substrate, occurrence of metazoan Konservat Fossil-lagerstätten, establishment of most invertebrate phyla, strong faunal provincialism, dominance of trilobites, generally warm climate but with possibleglacial-interglacial cycles in the later part, opening of the Iapetus Ocean,

Toward the spectrum of free polyethylene : Linear alkanes studied by carbon 1s photoelectron spectroscopy and theory

Trends in carbon 1s ionization energies for the linear alkanes have been investigated using third-generation synchrotron radiation. The study comprises CH4, C2H6, C3H8, C4H10, C5H12, C6H14, and C8H18. Both inter- and intramolecular shifts in ionization energy have been determined from gas-phase spectra and ab initio calculations. The shifts are decomposed into initial-state and final-state contrib

Vibrationally resolved photoelectron spectra of the carbon 1s and nitrogen 1s shells in hydrogen cyanide

Vibrational structures of the C1s and N1s photoelectron spectra of gas-phase HCN have been investigated using monochromated third-generation synchrotron radiation. Both spectra exhibit resolved fine structure associated with several vibrationally excited states. In the C1s spectrum a single vibrational progression is observed, while the N1s spectrum is more complex. High-level ab initio calculatio

"Hidden" vibrations in CO : Reinvestigation of resonant Auger decay for the C 1s → π* excitation

The higher vibrational levels of the C 1s→π* excitation in carbon monooxide (CO) were investigated by using resonant Auger electron spectroscopy. The absorption profile of the CO was recorded in the partial electron yield mode. The results showed that the vibrational states were not seen in a total yield absorption spectrum whereas they were shown to be discernable in a partial electron yield spec

Filtering core excitation spectra : Vibrationally resolved constant ionic state studies of N 1s → 2π core-excited NO

High-resolution electron spectroscopy studies of the NO molecule in the regions of the N 1s → 2π core excitations have been performed. By selecting electrons within certain binding energy ranges, either the Auger electron yield - a good approximation for the x-ray absorption spectrum - or the electrons emitted after decay to a particular ionic final state (constant ionic state (CIS)) were detected

A vibrationally resolved experimental study of the sulfur L-shell photoelectron spectrum of the CS2 molecule

The sulfur L-shell photoelectron spectrum of the carbon disulfide molecule has been studied using monochromated synchrotron radiation with a photon energy of 250 eV. The spectrum is atomic like, showing three major bands that can be associated with the sulfur (2p-1)2P3/2,12 and (2s-1)2S1/2 ionic states. A closer inspection shows that the 2P3/2 state is further split into two components separated b

Dynamical suppression of atomic peaks in resonant dissociative photoemission

Resonant excitation to the F1s-σ* dissociative state in hydrogen fluoride gives a photoelectron spectrum where the spectator part contains strong atomic lines but a participator part where such lines are lacking. We demonstrate that this contrasting behaviour between the two parts is due to a strong dynamical suppression of the resonant contribution, making direct main state photoionization the do

Femtosecond dissociation of ozone studied by the Auger Doppler effect

The peaks arising from the decay of the excited oxygen atom were studied. Fast dissociation of core-excited ozone was confirmed by the presence of Auger emission from atomic oxygen in the decay spectrum from the ozone OT 1s-σ*(7a1) state. No such emission was observed after excitation of the corresponding state on the central oxygen atom. An angle-dependent energy shift of the atomic lines was obs

Evidence against atomiclike resonant auger decay in N2 doubly excited core states by high-resolution experiments

The resonant Auger decay spectra associated with doubly excited core-hole states near the N 1s threshold in the nitrogen molecule was measured. Electron-yield spectrum was obtained by setting a kinetic-energy window at 384 eV and scanning across the threshold region. At ground 410, 414, and 416 eV, photon energy, three dominant structures were observed. The increased signal-to-background ratio, in

Nuclear motion driven by the Renner-Teller effect as observed in the resonant Auger decay to the X̃2Π electronic ground state of N2O+

The nuclear dynamics in the Nt 1s→π* in nitrous oxide was studied using the high resolution resonant Auger spectroscopy and ab initio quantum chemical calculations. For probing the nuclear motion of the system in the core-excited state, the frequency detuning technique was used. The results showed changes in vibrational structure for the Auger decay spectra and a strong influence of nuclear motion

Interference between direct and resonant channels in near-resonance photoemission in argon

The photoelectron spectra of argon was demonstrated during resonant photoemissions. The interference effects of the photoelectron spectra of argon was monitored by following the intensity of final states through resonant and direct channels. The need for a unified one-description of the ionization through a direct and core-excitation mediated channel was described.

Evidence for ultra-fast dissociation of molecular water from resonant Auger spectroscopy

We present direct evidence for ultra-fast dissociation of molecular water in connection photo-excitation of the O1s→4a1 resonance. The core-excited H2O molecules are shown to dissociate into core-excited O*H and neutral H on a time scale comparable to the core hole lifetime, i.e. a few femtoseconds. This conclusion is based on a resonant Auger study, qualitative arguments and ab initio calculation

Humans Perform Social Movements in Response to Social Robot Movements : Motor Intention in Human-Robot Interaction

In an experimental study of humans reactions to social motor intention (SMI) in a humanoid robot, we showed that SMI cause the emergence of social interaction between human and robot. We investigated whether people would respond differently to a humanoid robot depending on the kinematic profile of its movement. A robot placed a block on a table in front of a human subject in three different ways.