Mixed Magnetic and Electric Dipole Transition in s-Triazine

We have shown that the radiation pattern for absorption to the lowest energy excited singlet state of s‐triazine corresponds to that of a mixed electric and magnetic dipole transition. This was done by demonstrating, for the first time with an organic, the classic procedure of obtaining absorption coefficients for different k, ε̂, and Ĥ for a uniaxial arrangement of molecules. We find the 30 014 cm^(−1) transition of s‐triazine to be 26% magnetic and 74% electric dipole, hence the state symmetry is ^1 E in the crystal field, and ^1 E″ in the free molecule (D_(3h) )

Pufendorf, Samuel

During the last two decades, Samuel von Pufendorf’s (1632–1694) natural law philosophy has become the subject of renewed and growing attentiveness among intellectual historians and philosophers (Seidler 2015). In the late-seventeenth century and early eighteenth century, Pufendorf was the most widely-read moral and political philosopher in Europe, whose reputation is most clearly exemplified in the impressive number of translations and editions of his works. Pufendorfian natural law theory offered a shared vocabulary and conceptual possibilities for the discussion of morality, politics and interstate relations for numerous eighteenth-century thinkers, such as Christian Thomasius, the authors of the Scottish Enlightenment and Jean-Jacques Rousseau. Pufendorf spent large parts of his career in princely courts and portrayed the history of states and their natural law foundations in his widely circulated historical works (Seidler 1997). Moreover, he also wrote on the issues of theology and church-state relations (Döring 1992, Zurbuchen 1998).Peer reviewe

Thermal diffusion of supersonic solitons in an anharmonic chain of atoms

We study the non-equilibrium diffusion dynamics of supersonic lattice solitons in a classical chain of atoms with nearest-neighbor interactions coupled to a heat bath. As a specific example we choose an interaction with cubic anharmonicity. The coupling between the system and a thermal bath with a given temperature is made by adding noise, delta-correlated in time and space, and damping to the set of discrete equations of motion. Working in the continuum limit and changing to the sound velocity frame we derive a Korteweg-de Vries equation with noise and damping. We apply a collective coordinate approach which yields two stochastic ODEs which are solved approximately by a perturbation analysis. This finally yields analytical expressions for the variances of the soliton position and velocity. We perform Langevin dynamics simulations for the original discrete system which fully confirm the predictions of our analytical calculations, namely noise-induced superdiffusive behavior which scales with the temperature and depends strongly on the initial soliton velocity. A normal diffusion behavior is observed for very low-energy solitons where the noise-induced phonons also make a significant contribution to the soliton diffusion.Comment: Submitted to PRE. Changes made: New simulations with a different method of soliton detection. The results and conclusions are not different from previous version. New appendixes containing information about the system energy and soliton profile

Two-Dimensional Infrared Spectroscopy of Antiparallel β-Sheet Secondary Structure

We investigate the sensitivity of femtosecond Fourier transform two-dimensional infrared spectroscopy to protein secondary structure with a study of antiparallel β-sheets. The results show that 2D IR spectroscopy is more sensitive to structural differences between proteins than traditional infrared spectroscopy, providing an observable that allows comparison to quantitative models of protein vibrational spectroscopy. 2D IR correlation spectra of the amide I region of poly-L-lysine, concanavalin A, ribonuclease A, and lysozyme show cross-peaks between the IR-active transitions that are characteristic of amide I couplings for polypeptides in antiparallel hydrogen-bonding registry. For poly-L-lysine, the 2D IR spectrum contains the eight-peak structure expected for two dominant vibrations of an extended, ordered antiparallel β-sheet. In the proteins with antiparallel β-sheets, interference effects between the diagonal and cross-peaks arising from the sheets, combined with diagonally elongated resonances from additional amide transitions, lead to a characteristic “Z”-shaped pattern for the amide I region in the 2D IR spectrum. We discuss in detail how the number of strands in the sheet, the local configurational disorder in the sheet, the delocalization of the vibrational excitation, and the angle between transition dipole moments affect the position, splitting, amplitude, and line shape of the cross-peaks and diagonal peaks.

Silver staining of proteins in polyacrylamide gels

Silver staining is used to detect proteins after electrophoretic separation on polyacrylamide gels. It combines excellent sensitivity (in the low nanogram range) with the use of very simple and cheap equipment and chemicals. It is compatible with downstream processing, such as mass spectrometry analysis after protein digestion. The sequential phases of silver staining are protein fixation, then sensitization, then silver impregnation and finally image development. Several variants of silver staining are described here, which can be completed in a time range from 2 h to 1 d after the end of the electrophoretic separation. Once completed, the stain is stable for several weeks

Experimental studies of triplet exciton bands of molecular crystals

Methods of studying properties of triplet exciton states of organic crystals are presented with an emphasis on exposing the dimensionality of excitons. Results of isotopic replacement spectra for 1,4-dibromonaphthalene which is a linear chain, and for halogenated benzenes, which are likely to be linear chains, are presented. Luminescence studies of linear chain exciton systems are shown to yield information about the stationary states of small clusters. Finally some preliminary studies of two-photon spectra of naphthalene excitons are described

Spin polarization of the L-gap surface states on Au(111)

The electron spin polarization (ESP) of the L-gap surface states on Au(111) is investigated theoretically by means of first-principles electronic-structure and photoemission calculations. The surface states show a large spin-orbit induced in-plane ESP which is perpendicular to the in-plane wavevector, in close analogy to a two-dimensional electron gas with Rashba spin-orbit interaction. The surface corrugation leads to a small ESP component normal to the surface, being not reported so far. The surface-states ESP can be probed qualitatively and quantitatively by spin- and angle-resolved photoelectron spectroscopy, provided that the initial-state ESP is retained in the photoemission process and not obscured by spin-orbit induced polarization effects. Relativistic photoemission calculations provide detailed information on what photoemission set-ups allow to conclude from the photoelectron ESP on that of the surface states.Comment: 22 pages with 8 figure