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Studies of ion-molecule reactions at low temperatures are difficult because stray electric fields in the reaction volume affect the kinetic energy of charged reaction partners. We describe a new experimental approach to study ion-molecule…

It has been recently predicted theoretically that due to nuclear motion light and heavy hydrogen molecules exposed to strong electric field should exhibit substantially different tunneling ionization rates (O.I. Tolstikhin, H.J. Worner and…

Atomic Physics · Physics 2016-08-24 X. Wang , H. Xu , A. Atia-Tul-Noor , B. T. Hu , D. Kielpinski , R. T. Sang , I. V. Litvinyuk

We calculated reaction rate constants including atom tunneling for the hydrogen abstraction reaction CH3OH+H -> CH2OH+H2 with the instanton method. The potential energy was fitted by a neural network, that was trained to…

Chemical Physics · Physics 2020-09-10 April. M. Cooper , Johannes Kästner

We report on a study of cold reactive collisions between sympathetically-cooled molecular ions and laser-cooled atoms in an ion-atom hybrid trap. Chemical reactions were studied at average collision energies <Ecoll>/k > 20 mK, about two…

Atomic Physics · Physics 2015-06-11 Felix H. J. Hall , Stefan Willitsch

The energy dependence of the rates of the reactions between He$^+$ and ammonia (NY$_3$, Y= {H,D}), forming NY$_2^+$, Y and He as well as NY$^+$, Y$_2$ and He, and the corresponding product branching ratios have been measured at low…

We have measured the reaction rates of trapped, buffer gas cooled Th$^{3+}$ and various gases and have analyzed the reaction products using trapped ion mass spectrometry techniques. Ion trap lifetimes are usually limited by reactions with…

Atomic Physics · Physics 2015-05-20 L. R. Churchill , M. V. DePalatis , M. S. Chapman

Sets of systematic laboratory experiments are presented -- combining Ultra High Vacuum cryogenic and plasma-line deposition techniques -- that allow us to compare H/D isotopic effects in the reaction of H2O (D2O) ice with the hydroxyl…

Solar and Stellar Astrophysics · Physics 2015-11-09 T. Lamberts , G. Fedoseev , F. Puletti , S. Ioppolo , H. M. Cuppen , H. Linnartz

The $dp\to dp$ and $dd\to ^3He n$ reactions are considered in the energy range from few hundred MeV up to 1 GeV. The approach is based on the multiple-scattering theory, where the few-body collisions are presented through two-body ones. The…

Nuclear Theory · Physics 2011-08-31 Nadezhda Ladygina

The rate coefficients of various isotopic variations of the H2+ + H2 and H3+ + H2 reactions in the 10-250 K temperature range were measured using a cryogenic 22 pole radio frequency ion trap. The processes involving diatomic ions were found…

Solar and Stellar Astrophysics · Physics 2024-12-04 Miguel Jiménez-Redondo , Olli Sipilä , Pavol Jusko , Paola Caselli

To correctly model the abundances of interstellar complex organic molecules (iCOMS) in different environments, both formation and destruction routes should be appropriately accounted for. While several scenarios have been explored for the…

Solar and Stellar Astrophysics · Physics 2019-05-15 Daniela Ascenzi , Andrea Cernuto , Nadia Balucani , Paolo Tosi , Cecilia Ceccarelli , Luca Matteo Martini , Fernando Pirani

The ion-molecule reactions $\text{D}_2^++\text{NH}_3$ and $\text{D}_2^++\text{ND}_3$ are studied at low collision energies ($E_{\text{coll}}$ from zero to $\sim k_\textrm{B}\cdot 50\,\text{K}$), with the $\text{D}_2^+$ ions in the ground…

Chemical Physics · Physics 2024-03-05 Raphaël Hahn , David Schlander , Valentina Zhelyazkova , Frédéric Merkt

Full quantum dynamics calculations have been carried out for the ionic reaction 4He2+ + 3He and state-to-state reactive probabilities have been obtained using both a time-dependent (TD) and a time-independent (TI) approach. An accurate…

Chemical Physics · Physics 2009-11-11 Enrico Bodo , Manuel Lara , Franco A. Gianturco

We study the dynamical fluctuations of various particle yield ratios at different incident energies. Assuming that the particle production yields in the hydronic final state are due to equilibrium chemical processes ($\gamma=1$), the…

High Energy Physics - Phenomenology · Physics 2015-05-13 A. Tawfik

We investigate the atmospheric oxidation of mercury Hg(0) by halogens, initiated by Br and I to yield Hg(I), and continued by I, Br, BrO, ClO, IO, NO2 and HO2 to yield Hg(II) or Hg(0), using computational methods with a focus on the…

Chemical Physics · Physics 2025-01-13 Svend L. Bager , Luna Zamok , Stephan P. A. Sauer , Matthew S. Johnson

Quantum effects in condensed matter normally only occur at low temperatures. Here we show a large quantum effect in high-pressure liquid hydrogen at thousands of Kelvins. We show that the metallization transition in hydrogen is subject to a…

Materials Science · Physics 2021-06-09 Sebastiaan van de Bund , Heather Wiebe , Graeme J. Ackland

Trapped Be+ ions are a leading platform for quantum information science [1], but reactions with background gas species, such as H2 and H2O, result in qubit loss. Our experiment reveals that the BeOH+ ion is the final trapped ion species…

Chemical Physics · Physics 2021-11-17 Tiangang Yang , Bin Zhao , Gary K. Chen , Hua Guo , Wesley C. Campbell , Eric R. Hudson

A novel pathway for the formation of multi-particle-multi-hole (np-mh) excited states in rare isotopes is reported from highly energy- and momentum-dissipative inelastic-scattering events measured in reactions of an intermediate-energy beam…

We reveal the hydrogen isotope effect of three chemical reactions, i.e, the reflection, the absorption and the penetration ratios, by classical molecular dynamics simulation with a modified Brenner's reactive empirical bond order (REBO)…

Materials Science · Physics 2007-05-23 Nakamura Hiroaki , Arimichi Takayama , Astushi Ito

We confront the hypothesis of chemical freeze-out in ultra-relativistic heavy-ion collisions with the hypothesis of large modifications of hadron masses in nuclear medium. We find that the thermal-model predictions for the ratios of…

Nuclear Theory · Physics 2009-10-31 W. Florkowski , W. Broniowski
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