Inverse isotope effect of ZrMnx (x=1.9 or 2.0)-Q2 (Q=H or D) system

2013 ◽  
Vol 74 (8) ◽  
pp. 1174-1178 ◽  
Author(s):  
Masanori Hara ◽  
Takafumi Yamamoto ◽  
Katsuhiko Nishimura ◽  
Satoshi Akamaru ◽  
Kuniaki Watanabe ◽  
...  
Keyword(s):  
Isotope Effect ◽  
Inverse Isotope Effect

scholarly journals Nitrogen isotope effects can be used to diagnose N transformations in wastewater anammox systems

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Paul M. Magyar ◽  
Damian Hausherr ◽  
Robert Niederdorfer ◽  
Nicolas Stöcklin ◽  
Jing Wei ◽  
...  
Keyword(s):  
Isotope Effect ◽  
Isotope Composition ◽  
Isotope Effects ◽  
Nitrogen Isotope ◽  
Anammox Bacteria ◽  
Ammonium Oxidation ◽  
Experimental Conditions ◽  
N Transformations ◽  
Natural Systems ◽  
Inverse Isotope Effect

AbstractAnaerobic ammonium oxidation (anammox) plays an important role in aquatic systems as a sink of bioavailable nitrogen (N), and in engineered processes by removing ammonium from wastewater. The isotope effects anammox imparts in the N isotope signatures (15N/14N) of ammonium, nitrite, and nitrate can be used to estimate its role in environmental settings, to describe physiological and ecological variations in the anammox process, and possibly to optimize anammox-based wastewater treatment. We measured the stable N-isotope composition of ammonium, nitrite, and nitrate in wastewater cultivations of anammox bacteria. We find that the N isotope enrichment factor 15ε for the reduction of nitrite to N2 is consistent across all experimental conditions (13.5‰ ± 3.7‰), suggesting it reflects the composition of the anammox bacteria community. Values of 15ε for the oxidation of nitrite to nitrate (inverse isotope effect, − 16 to − 43‰) and for the reduction of ammonium to N2 (normal isotope effect, 19–32‰) are more variable, and likely controlled by experimental conditions. We argue that the variations in the isotope effects can be tied to the metabolism and physiology of anammox bacteria, and that the broad range of isotope effects observed for anammox introduces complications for analyzing N-isotope mass balances in natural systems.

Dynamically Bifurcating Hydride Transfer Mechanism and Origin of Inverse Isotope Effect for Heterodinuclear AgRu-Catalyzed Alkyne Semihydrogenation

ACS Catalysis ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 2657-2663 ◽  
Author(s):  
Ying Zhang ◽  
Malkanthi K. Karunananda ◽  
Hsien-Cheng Yu ◽  
Kyle J. Clark ◽  
Wendy Williams ◽  
...  
Keyword(s):  
Isotope Effect ◽  
Hydride Transfer ◽  
Transfer Mechanism ◽  
Inverse Isotope Effect

scholarly journals On the “inverse” isotope effect in organic superconductors: new findings and implications

2001 ◽  
Vol 120 (1-3) ◽  
pp. 713-714 ◽  
Author(s):  
Aravinda M. Kini ◽  
John A. Schlueter ◽  
Brian H. Ward ◽  
Urs W. Geiser ◽  
H.Hau Wang
Keyword(s):  
Isotope Effect ◽  
Organic Superconductors ◽  
New Findings ◽  
Inverse Isotope Effect

Role of tetrahedrally coordinated dopants in palladium hydrides on their superconductivity and inverse isotope effect

2019 ◽  
Vol 31 (7) ◽  
pp. 075703 ◽  
Author(s):  
S Ostanin ◽  
V Borisov ◽  
D V Fedorov ◽  
E I Salamatov ◽  
A Ernst ◽  
...  
Keyword(s):  
Isotope Effect ◽  
Inverse Isotope Effect

Anharmonicity and the inverse isotope effect in the palladium-hydrogen system

1992 ◽  
Vol 45 (21) ◽  
pp. 12405-12414 ◽  
Author(s):  
Barry M. Klein ◽  
Ronald E. Cohen
Keyword(s):  
Isotope Effect ◽  
Hydrogen System ◽  
Inverse Isotope Effect

Origin of “Inverse Isotope Effect” of Hydrogen Diffusion in Palladium

2011 ◽  
Vol 312-315 ◽  
pp. 295-300 ◽  
Author(s):  
Osamu Yoshinari
Keyword(s):  
Isotope Effect ◽  
Diffusion Coefficients ◽  
Hydrogen Diffusion ◽  
Three Dimensional ◽  
Diffusion Path ◽  
Jump Processes ◽  
First Principles Calculation ◽  
Elastic Band ◽  
Experimental Values ◽  
Inverse Isotope Effect

The diffusion coefficients of hydrogen (H) and deuterium (D) in Pd were determined in the frame of a quantum mechanical consideration. The three dimensional (3D) wave functions and eigenenergies of H and D at a stable octahedral (o) site and a metastable tetrahedral (t) site were determined by solving the Schrödinger equation with 3D potentials obtained by the first principles calculation. The states of H and D along the diffusion path were also determined by using transient potentials which were obtained with an aid of the nudged elastic band method. The magnitudes of tunneling matrix elements (J) were evaluated from the eigenenergy curves along the diffusion path. In the Pd-H system, thermally activated tunneling transitions are dominant jump processes. On the other hand, in the Pd-D system, it is revealed that a transition via an extended state where the wave function spreads both to o- and t-sites also has a considerable contribution to the diffusion. The calculated diffusion coefficients for H and D quantitatively agreed with experimental values and the so-called inverse isotope effect was reproduced.

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