A5005046584- Advanced Chemical Physics Studies
- Spectroscopy and Laser Applications
- Cold Atom Physics and Bose-Einstein Condensates
- Quantum, superfluid, helium dynamics
- Atmospheric Ozone and Climate
- Spectroscopy and Quantum Chemical Studies
- Atomic and Subatomic Physics Research
- Molecular Spectroscopy and Structure
- Atomic and Molecular Physics
- Mass Spectrometry Techniques and Applications
- Laser-Matter Interactions and Applications
- Astrophysics and Star Formation Studies
- Photochemistry and Electron Transfer Studies
- Inorganic Fluorides and Related Compounds
- Various Chemistry Research Topics
- Molecular spectroscopy and chirality
- Strong Light-Matter Interactions
- Advanced NMR Techniques and Applications
- Atmospheric and Environmental Gas Dynamics
- Quantum optics and atomic interactions
- Atmospheric chemistry and aerosols
- Magnetism in coordination complexes
- Astro and Planetary Science
- Matrix Theory and Algorithms
- Magnetic confinement fusion research
Radboud University Nijmegen
2015-2025
Radboud Institute for Molecular Life Sciences
2005-2023
Radboud University Medical Center
2005-2023
University of Montana
2016-2022
University of Missouri
2017
Fritz Haber Institute of the Max Planck Society
2006-2016
Chalmers University of Technology
2016
University of Nevada, Las Vegas
2015
University of Bristol
2009
Université Paris-Sud
2009
A force field for water has been developed entirely from first principles, without any fitting to experimental data. It contains both pairwise and many-body interactions. This predicts the properties of dimer liquid in excellent agreement with experiments, a previously elusive objective. Precise knowledge intermolecular interactions will facilitate better understanding this ubiquitous substance.
Molecular scattering behavior has generally proven difficult to study at low collision energies. We formed a molecular beam of OH radicals with narrow velocity distribution and tunable absolute by passing the through Stark decelerator. The transition probabilities for inelastic Xe atoms were measured as function energy in range 50 400 wavenumbers, an overall resolution about 13 wavenumbers. cross-sections near energetic thresholds was accurately measured, excellent agreement obtained derived...
The authors present a new potential energy curve, electric dipole moment function, and spin-orbit coupling function for OH in the XΠ2 state, based on high-level ab initio calculations. These properties, combined with spectroscopically parametrized lambda-type doubling Hamiltonian, are used to compute Einstein A coefficients photoabsorption cross sections Meinel transitions. investigate effect of lifetimes rovibrationally excited states. Comparing their results earlier calculations, they...
In molecular collisions, resonances occur at specific energies where the colliding particles temporarily form quasi-bound complexes, resulting in rapid variations energy dependence of scattering cross sections. Experimentally, it has proven challenging to observe such resonances, especially differential We report observation resonance fingerprints state-to-state sections for inelastic NO-He collisions 13 19 cm$^{-1}$ range with 0.3 resolution. The observed structures were excellent agreement...
When Molecules Collide As advances in computing power and algorithm design parallel the increasing sophistication of experimental apparatus, theory measurement are perpetually trading places as to which can detail dynamics molecular interactions more precisely. At present, collisions an atom with a diatomic molecule be studied comparably both domains. In contrast, two diatomics each bearing unpaired electron manifest too many degrees freedom for computational quantum mechanics. Kirste et al....
The lifetime of nonreactive ultracold bialkali gases was conjectured to be limited by sticky collisions amplifying three-body loss. We show that the sticking times were previously overestimated and do not support this hypothesis. find electronic excitation NaK+NaK collision complexes trapping laser leads experimentally observed two-body calculate rate with a quasiclassical, statistical model employing ab initio potentials transition dipole moments. Using longer wavelengths or repulsive box...
Collisions between cold polar molecules represent a fascinating research frontier but have proven hard to probe experimentally. We report measurements of inelastic cross sections for collisions nitric oxide (NO) and deuterated ammonia (ND3) at energies 0.1 580 centimeter-1, with full quantum state resolution. At below the ~100-centimeter-1 well depth interaction potential, we observed backward glories originating from peculiar U-turn trajectories. 0.2 breakdown Langevin capture model, which...
Bottom-up quantum simulators have been developed to quantify the role of various interactions, dimensionality, and structure in creating electronic states matter. Here, we demonstrated a solid-state simulator emulating molecular orbitals, based solely on positioning individual cesium atoms an indium antimonide surface. Using scanning tunneling microscopy spectroscopy, combined with ab initio calculations, showed that artificial could be made from localized created patterned rings. These...
A new ab initio pair potential for water was generated by fitting 2510 interaction energies computed the use of symmetry-adapted perturbation theory (SAPT). The site–site functional form, named SAPT-5s, is simple enough to be applied in molecular simulations condensed phases and at same time reproduces points with accuracy exceeding that elaborate SAPT-pp form used earlier [J. Chem. Phys. 107, 4207 (1997)]. SAPT-5s has been shown quantitatively predict dimer spectra, see following paper...
In order to reduce the memory requirements of quantum reactive scattering calculations based on delocalized basis sets, we use a discrete in single interaction region coordinate system, resulting sparse Hamiltonian matrix. The set linear equations is solved via an iterative method which exploits their sparsity. Other important features our formalism are truncated grid and distorted waves used shrink region, therefore size. We demonstrate assess its efficiency for reaction D+H2→DH+H, at total...
A six-dimensional interaction potential for the water dimer has been fitted to ab initio energies computed at 2510 configurations. These were obtained by combining supermolecular second-order extrapolated complete basis set limit from up quadruple-zeta quality sets with contribution coupled-cluster method including single, double, and noniterative triple excitations in a triple-zeta set. All augmented diffuse functions supplemented midbond functions. The have using an analytic form induction...
We report a new full-dimensional potential energy surface (PES) for the water dimer, based on fitting energies at roughly 30,000 configurations obtained with coupled-cluster single and double, perturbative treatment of triple excitations method using an augmented, correlation consistent, polarized zeta basis set. A global dipole moment Moller-Plesset perturbation theory results these is also reported. The PES used in rigorous quantum calculations intermolecular vibrational frequencies,...
The six-dimensional CC-pol interaction potential for the water dimer was used to predict properties of and liquid water, in latter case after being supplemented by a nonadditive potential. All results were obtained purely from first principles, i.e., without any fitting experimental data. Calculations vibration-rotation-tunneling levels (H(2)O)(2) (D(2)O)(2), very sensitive test surface, gave good agreement with high-resolution spectra. Also virial coefficients agree well measured values....
We derive a quasiclassical expression for the density of states (DOS) an arbitrary, ultracold, $N$-atom collision complex, general potential energy surface (PES). establish accuracy our method by comparing to exact quantum results ${\mathrm{K}}_{2}\text{\ensuremath{-}}\mathrm{Rb}$ and NaK-NaK systems, with isotropic model PESs. Next, we calculate DOS accurate PES be 0.124 $\ensuremath{\mu}{\mathrm{K}}^{\ensuremath{-}1}$, associated Rice-Ramsperger-Kassel-Marcus sticking time 6.0...
The pathway toward the tailored synthesis of materials starts with precise characterization conformational properties and dynamics individual molecules. Electron spin resonance (ESR)-based scanning tunneling microscopy can potentially address molecular structure unprecedented resolution. Here, we determine fine geometry an titanium-hydride molecule, utilizing a combination newly developed millikelvin ESR microscope in vector magnetic field ab initio approaches. We demonstrate strikingly...
Nearly exact six-dimensional quantum calculations of the vibration–rotation–tunneling (VRT) levels water dimer for values rotational numbers J and K ⩽2 show that SAPT-5s pair potential presented in preceding paper (paper I) gives a good representation experimental high-resolution far-infrared spectrum dimer. After analyzing sensitivity transition frequencies with respect to linear parameters we could further improve this by using only one experimentally determined tunneling splittings ground...
We present the first pair plus three-body potential of water from ab initio calculations that quantitatively reproduces experimental far-infrared spectra dimer and trimer. The spectrum was obtained through rigorous six-dimensional quantum vibration-rotation-tunneling levels. interactions, together with potential, produce an accurate representation hydrogen bond torsional levels
Neutral molecules, isolated in the gas phase, can be prepared a long-lived excited state and stored trap. The long observation time afforded by trap then exploited to measure radiative lifetime of this monitoring temporal decay population This method is demonstrated here used benchmark Einstein A coefficients Meinel system OH. pulsed beam vibrationally OH radicals Stark decelerated loaded into an electrostatic quadrupole upper Lamda-doublet component Chi2Pi3/2, v=1, J=3/2 level determined as...
Constructing accurate global potential energy surfaces (PESs) describing chemically reactive molecule-molecule collisions of alkali metal dimers presents a major challenge. To be suitable for quantum scattering calculations, such PESs must represent accurately three- and four-body interactions, describe conical intersections, have proper asymptotic form at the long range. Here, we demonstrate that potentials can obtained by Gaussian Process (GP) regression merged with analytic expansions We...
At low energies, the quantum wave-like nature of molecular interactions result in unique scattering behavior, ranging from universal Wigner laws near zero Kelvin to occurrence resonances at higher energies. It has proven challenging experimentally probe individual waves underlying these phenomena. We report measurements state-to-state integral and differential cross sections for inelastic NO-He collisions 0.2 - 8.5 cm$^{-1}$ range with 0.02 resolution. study onset resonance regime by probing...
Feshbach resonances are fundamental to interparticle interactions and become particularly important in cold collisions with atoms, ions, molecules. Here we present the detection of a benchmark system for strongly interacting highly anisotropic -- molecular hydrogen ions colliding noble gas atoms. The launched by Penning ionization exclusively populating that span both short- long-range parts interaction potential. We resolved all final channels tomographic manner using ion-electron...