Product vibrational state distributions in the photodissociation of iodine - rare gas clusters

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Single-Hessian Gaussian wavepacket dynamics (GWD) significantly reduces the computational burden of Heller’s local harmonic GWD while maintaining comparable accuracy in approximating vibronic spectra. Here, we provide a new, symplectic derivation of the equations of motion of single-Hessian GWD and show that, unlike the local harmonic version, this method conserves the non-canonical symplectic structure on the manifold of Gaussian wavepackets and—for bounded dynamics in smooth potentials—avoids the drift of

Nanoscale chemical imaging enabled by atomic force microscopy-infrared spectroscopy (AFM-IR) provides valuable insights into the complex structures and chemical compositions of materials and biological samples. While AFM-IR has been applied to subsurface imaging, the underlying mechanisms, particularly in nonplanar geometries and complex heterogeneous structures, remain underexplored. This study presents a theoretical analysis and experimental validation of AFM-IR for imaging subsurface features within orga

Key cellular functions depend on the transduction of extracellular mechanical signals by specialized membrane receptors including adhesion G-protein coupled receptors (aGPCRs). While recently solved structures support aGPCR activation through shedding of the extracellular GAIN domain, the molecular mechanisms underpinning receptor mechanosensing remain poorly understood. When probed using single-molecule atomic force spectroscopy and molecular simulations, ADGRG1 GAIN dissociated from its tethered agonist a

The exceptional enhancement of Raman scattering by localized plasmonic resonances in the near field of metallic nanoparticles, surfaces or tips (SERS, TERS) has enabled spectroscopic fingerprinting down to the single molecule level. The conventional explanation attributes the enhancement to the subwavelength confinement of the electromagnetic field near nanoantennas. Here, we introduce a new model that also accounts for the dynamical nature of the plasmon-molecule interaction. We thereby reveal an enhanceme

Including quantum mechanical effects on the dynamics of nuclei in the condensed phase is challenging, because the complexity of exact methods grows exponentially with the number of quantum degrees of freedom. Efforts to circumvent these limitations can be traced down to two approaches: methods that treat a small subset of the degrees of freedom with rigorous quantum mechanics, considering the rest of the system as a static or classical environment, and methods that treat the whole system quantum mechanicall

This paper presents a new algorithm for classifying distributions. The algorithm combines the principle of margin maximization and a kernel trick, applied to distributions. Thus, it combines the discriminative power of support vector machines and the well-developed framework of generative models. It can be applied to a number of real-life tasks which include data represented as distributions. The algorithm can also be applied for introducing some prior knowledge on invariances into a discriminative model. W

The dynamics of the ferric CN complexes of the heme proteins Myoglobin and Hb I from the clam Lucina pectinata upon Soret band excitation is monitored using IR and broad band visible pump-probe spectroscopy. The transient response in the UV-vis spectral region does not depend on the heme pocket environment and is very similar to that known for ferrous proteins. The main feature is an instantaneous, broad, short-lived absorption signal that develops into a narrower red-shifted Soret band. Significant transie

Plasma created during electrical discharge machining is systematically investigated using optical emission spectroscopy. Typical spectra show a strong H-alpha and continuum radiation, with many lines emitted by impurities coming from electrode and workpiece materials. The dielectric molecules are cracked by the discharge. Changing polarity affects the electrode wear and workpiece erosion rates, which can be qualitatively seen on the spectra. Time-resolved spectroscopy shows that the plasma density reaches 2

The translational dynamics of CF3 in liquid helium have been investigated by photodissociating CF3I dissolved in helium droplets consisting of several thousands of atoms. The velocity distribution of CF3 fragments that have escaped from the droplets has been determined using ion imaging techniques and is found to be considerably shifted to lower speeds with respect to the photodissociation of gas phase CF3I. The fragments furthermore show a speed dependent angular distribution that is isotropic for the slow

Light Induced Chemical Vapour Deposition (LICVD) of titanium dioxide thin films is studied in this work. It is shown that this technique enables to deposit locally and selectively a chosen crystalline phase with a precise controlled thickness at low substrate temperature, allowing even the use of polymer substrates. A home made LICVD reactor was set up, consisting of a main chamber in which the substrate was placed on a temperature controlled plate and could be irradiated perpendicularly through a window by

Spectroscopic measurements on ethylene were performed using a quasi-room-temperature quantum cascade (QC) laser operated in pulsed mode in the 10.3 μm range. Using transmission spectroscopy, a broadening of the ethylene absorption spectrum was observed with increasing laser pulse duration, due to an increase of the laser linewidth. This linewidth was determined from the measured absorption spectra, showing a value of 0.04 cm-1 for a 20 ns pulse duration and an enhancement coefficient of 6.5 × 10-3 cm -1 per

The infrared reflectance of the transition-metal chalcogenide 1T-TaS2 has been measured at temperatures from 30 K to 360 K over 30-45 000 cm(-1) (4 meV-5.5 eV). The optical conductivity was obtained by Kramers-Kronig analysis. At 360 K only modest traces of the phonon lines are noticeable. The phonon modes are followed by a pseudo-gap-like increase of the optical conductivity, with direct optical transitions observed at frequencies above 1 eV. As the temperature decreases, the low-frequency conductivity als

Spectromicroscopy with the imaging technique of X-ray photoelectron emission microscopy (X-PEEM) is a microchemical analytical tool installed in many synchrotron radiation laboratories, and which is finding application in diverse fields of research. The method of sample analysis, X-ray absorption spectroscopy, does not encounter the same problems as X-ray photoemission spectroscopy when sample charging occurs, hence even good insulators may often be analyzed without any apparent artifacts in images or spect

The distribution of soil microorganisms is generally believed to be patchy and to reflect habitat heterogeneity. Despite this general rule, the amount of existing data oil species distribution patterns is scarce. Testate amoebae (Protozoa; Rhizopoda) are an important component of soil microbial communities and are increasingly used in ecological and paleoecological studies of Sphagnum-dominated peatlands, but data on the spatial structure of communities are completely lacking. This is an important aspect si

We report the fluorescence and excitation spectra of size selected Ag4 deposited in an argon matrix. The main fluorescence peak for Ag4 is observed at 458 nm. The excitation spectrum for this emission is in good agreement with recent theoretical calculations and photodepletion experiments.

Time-resolved fluorescence spectra for C60 mols. embedded in Ne and Ar matrixes and C70 in Ne matrixes were recorded using a synchroscan streak camera. In the case of C60, the decay times of the S1 state are identical for all fluorescence bands confirming that it is a state of mixed T1g, T2g, and Gg characters. Its lifetime is detd. by the intersystem crossing rate to the triplet manifold which increases in going from Ar to Ne matrixes. This is attributed to a change of the dominant symmetry character of S1

Radiative transfer is often the dominant energy transport channel in inertial confinement fusion experiments. It is a basic process needed in order to understand the behaviour of astrophysical plasmas, like stellar atmospheres and the inner parts of stars. Opacities account for photon absorption in matter. During decades, opacities have been numerically calculated on the basis of different atomic models. Before the nineties, no direct measurement of opacities spectra has been performed. The first experiment

Dynamics is discussed of photodissocn. of chlorine in noble gas matrixes. Dissocn. on repulsive surfaces, harpoon reactions and predissocn. of bound states by curve crossing are discussed using the distribution of electronic states of chlorine in the matrix. It is shown that electronic states and particularly Rydberg states of chlorine as well as ionic and charge-transfer states are significantly modified by the matrix environment. 22 Refs. [on SciFinder (R)]

Sequential pumping of the local OH stretch vibrations in hydrogen peroxide using infrared-optical double resonance permits spectroscopic access to the 4-nu(OH) + nu(OH)' combination level. Analysis of the rotationally resolved vibrational overtone spectra generated by this technique determines approximate rotational constants for this level and a value of 17 051.8 +/- 3.4 cm-1 for the O-O bond dissociation energy. The linewidths of individual zeroth-order rotational transitions increase sharply with increas

The influence of the fluence, intensity, and time on rate coeffs. and product yields in collisionless unimol. reactions induced by monochromatic IR is discussed in terms of the logarithmic reactant fluence plots. Model calcns. for several archetypes of such plots are presented, based on solns. of the Pauli master equation and solns. of the quantum mech. equations of motion for spectra involving many states at each level of excitation. Exptl. examples re-evaluated from the literature and new measurements on

Product vibrational state distributions in the photodissociation of iodine - rare gas clusters

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On the single-Hessian Gaussian wavepacket dynamics

Experimental and Theoretical Insights Into Nanoscale Afm-ir Imaging of Complex Heterogeneous Structures

Uncovering and engineering the mechanical properties of the adhesion GPCR ADGRG1 GAIN domain

Molecular cavity optomechanics as a theory of plasmon-enhanced Raman scattering

Communication: On the consistency of approximate quantum dynamics simulation methods for vibrational spectra in the condensed phase

A Kernel Classifier for Distributions

Time-resolved visible and infrared study of the Cyano complexes of Myoglobin and of Hemoglobin I from Lucina pectinata

Optical emission spectroscopy of electrical discharge machining plasma

Imaging the Translational Dynamics of CF3 in Liquid Helium Droplets

Selective light induced chemical vapour deposition of titanium dioxide thin films

Ethylene spectroscopy using a quasi-room-temperature quantum cascade laser

Phonon anomaly at the charge ordering transition in 1T-TaS2

Charging phenomena in PEEM imaging and spectroscopy

Horizontal distribution patterns of testate amoebae (Protozoa) in a Sphagnum magellanicum carpet

Fluorescence and excitation spectra of Ag4 in an argon matrix

Picosecond studies of the intramolecular relaxation processes in isolated C60 and C70 molecules

Calcul des opacités de plasmas denses. Eclatement du spectre dû aux interactions électroniques dans le cas du fer

Cage effect and molecular dynamics of Cl2 in rare gas solids

Vibrational overtone spectroscopy of the 4νOH+νOH’ combination level of HOOH via sequential local mode–local mode excitation

The dependence of rate coefficients and product yields upon fluence, intensity, and time in unimolecular reactions induced by monochromatic infrared radiation