Microscopic Structure of Liquid Nitric Oxide.

The microscopic structure of nitric oxide is investigated using neutron scattering experiments. The measurements are performed at various temperatures between 120 and 144 K and at pressures between 1.1 and 9 bar.

Experimental and modeling evidence for structural crossover in supercritical CO_{2}.

The physics of supercritical states is understood to a much lesser degree compared to subcritical liquids. Carbon dioxide, in particular, has been intensely studied, yet little is known about the supercritical part of its phase diagram. Here, we combine neutron scattering experiments and molecular dynamics simulations and demonstrate the structural crossover at the Frenkel line.

Collisional excitation of interstellar PO(XΠ) by He: new ab initio potential energy surfaces and scattering calculations.

We present the first ab initio potential energy surfaces (PESs) for the PO(XΠ)-He van der Waals system. The PESs were obtained using the open-shell partially spin-restricted coupled cluster approach with single, double and perturbative triple excitations [UCCSD(T)]. The augmented correlation-consistent polarized valence triple-zeta (aug-cc-pVTZ) basis set was employed supplemented by mid-bond functions.

Collision energy dependence of state-to-state differential cross sections for rotationally inelastic scattering of HO by He.

The inelastic scattering of HO by He as a function of collision energy in the range 381 cm to 763 cm at an energy interval of approximately 100 cm has been investigated in a crossed beam experiment using velocity map imaging. Change in collision energy was achieved by varying the collision angle between the HO and He beam. We measured the state-to-state differential cross section (DCS) of scattered HO products for the final rotational states J = 1, 1, 2 and 4.

Collisional excitation of CH(X²Π) by He: new ab initio potential energy surfaces and scattering calculations.

We present a new set of potential energy surfaces (PESs) for the CH(X(2)Π)-He van der Waals system. Ab initio calculations of the CH-He PES were carried out using the open-shell single- and double-excitation coupled cluster approach with non-iterative perturbational treatment of triple excitations [RCCSD(T)]. The augmented correlation-consistent polarized valence quadruple-zeta (aug-cc-pVQZ) basis set was employed augmented by mid-bond functions.

Crystal structure of bromido-nitro-syl-bis(tri-phenyl-phosphane-κP)nickel(II).

The asymmetric unit of the title complex, [NiBr(NO){P(C6H5)3}2], comprises two independent mol-ecules each with a similar configuration. The Ni(II) cation is coordinated by one bromide anion, one nitrosyl anion and two tri-phenyl-phosphane mol-ecules in a distorted BrNP2 tetra-hedral coordination geometry. The coordination of the nitrosyl group is non-linear, the Ni-N-O angles being 150.

Differential and integral cross sections in OH(X) + Xe collisions.

Differential cross sections (DCSs) for inelastic collisions of OH(X) with Xe have been measured at a collision energy of 483 cm(-1). The hydroxyl (OH) radicals were initially prepared in the X(2)Π3/2 (v = 0, j = 1.5, f) level using the hexapole electric field selection method.

New ab initio potential energy surfaces for the ro-vibrational excitation of OH(X(2)Π) by He.

We present a new set of three-dimensional potential energy surfaces (PES) for the OH(X(2)Π)-He van der Waals system, which explicitly takes into account the OH vibrational motion. Ab initio calculations of the OH-He PES were carried out using the open-shell single- and double-excitation coupled cluster approach with non-iterative perturbational treatment of triple excitations [RCCSD(T)]. The augmented correlation-consistent aug-cc-pVXZ (X = Q, 5, 6) basis sets were employed, and the energies obtained were then extrapolated to the complete basis set (CBS) limit.

Potential energy surface and rovibrational energy levels of the H2-CS van der Waals complex.

Owing to its large dipole, astrophysicists use carbon monosulfide (CS) as a tracer of molecular gas in the interstellar medium, often in regions where H(2) is the most abundant collider. Predictions of the rovibrational energy levels of the weakly bound complex CS-H(2) (not yet observed) and also of rate coefficients for rotational transitions of CS in collision with H(2) should help to interpret the observed spectra. This paper deals with the first goal, i.

Inelastic scattering of hydroxyl radicals with helium and argon by velocity-map imaging.

The hydroxyl radical (OH) is one of the most interesting molecules in molecular dynamics. In particular, inelastic collisions of free radicals such as OH are profoundly important in environments ranging from combustion to astrochemistry. However, measuring the velocities of OH molecules in specific internal quantum states has proven to be very difficult.

Orientation and alignment depolarization in OH(X 2Pi)+Ar/He collisions.

The depolarization of OH(X (2)Pi(3/2),v=0,J=1.5-6.5,e) rotational angular momentum (RAM) in collisions with He and Ar under thermal conditions (298 K) has been studied using two-color polarization spectroscopy (PS).

Do vectors point the way to understanding energy transfer in molecular collisions?

This tutorial review examines the proposition that vector properties reveal more about the underlying potential energy surfaces controlling the inelastic exchange of energy in intermolecular collisions than conventional scalar measurements. Exciting recent experimental progress is summarized in the form of six selected cases studies. The new information that has been extracted is compared with the predictions of complementary theory.

Rotational angular momentum polarization: the influence of stray magnetic fields.

We show that weak residual magnetic fields can significantly affect the preparation and measurement of molecular rotational angular momentum alignment in a typical gas-phase stereodynamics apparatus. Specifically, polarization spectroscopy, a third-order nonlinear spectroscopic technique, is used to prepare and probe the collisional and noncollisional losses of rotational angular momentum alignment of OH X (2)Pi. Residual magnetic fields of the order of the geomagnetic field are shown to have a significant effect on the prepared polarization on a submicrosecond timescale.

Inelastic scattering of OH(X2Pi) with Ar and He: a combined polarization spectroscopy and quantum scattering study.

One-colour polarization spectroscopy (PS) on the OH A (2)Sigma(+)- X (2)Pi(0,0) band has been used to measure the removal of bulk rotational angular momentum alignment of ground-state OH(X (2)Pi) in collisions with He and Ar. Pseudo-first-order PS signal decays at different collider partial pressures were used to determine second-order decay rate constants for the X (2)Pi(3/2), J = 1.5-6.