| 1. |
- Frankcombe, Terry J, et al.
(författare)
-
Adiabatic Capture Theory Applied to N + NH N2 + H at Low Temperature
- 2007
-
Ingår i: The journal of physical chemistry. A. - : American Chemical Society (ACS). - 1089-5639 .- 1520-5215. ; 111:50, s. 13163-13167
-
Tidskriftsartikel (refereegranskat)abstract
- The adiabatic capture centrifugal sudden approximation (ACCSA) has been applied to the ground state reaction N + NH N2 + H over the temperature range 2-300 K using an existent potential energy surface. The resultant thermal rate constants are in agreement with available rate constants from quasi-classical trajectory calculations but are significantly larger than the available experimentally derived rate. The calculated rate constants monotonically increase with increasing temperature but could only be approximately described with a simple Arrhenius-like form. Subtle quantum effects are evident in the initial rotational state resolved cross sections and rate constants.
|
|
| 2. |
- Frankcombe, Terry J, et al.
(författare)
-
An Adiabatic Capture Theory and Quasiclassical Trajectory Study of C plus NO and O plus CN on the (2)A ', (2)A '', and (4)A '' Potential Energy Surfaces
- 2012
-
Ingår i: Journal of Physical Chemistry A. - : American Chemical Society (ACS). - 1089-5639 .- 1520-5215. ; 116:19, s. 4705-4711
-
Tidskriftsartikel (refereegranskat)abstract
- The adiabatic capture centrifugal sudden approximation (ACCSA) has been applied to the C + NO and O + CN reactions, along with quasiclassical trajectory simulations. Existing global analytic fits to the potential energy surfaces of the CNO system in the (2)A', (2)A '', and (4)A '' electronic states have been used. Thermal rate constants for reaction in each of the electronic states have been calculated. In all cases a strong temperature dependence is evident in the calculated rate constants. The agreement between the calculated adiabatic capture and quasiclassical trajectory rate constants is excellent in some cases, but these rate constants differ considerably in other cases. This behavior is analyzed in terms of the anisotropy of the potential energy surfaces. On the basis of this analysis, we propose a new diagnostic for the reliability of ACCSA capture calculations.
|
|
| 3. |
|
|
| 4. |
- Frankcombe, Terry J, et al.
(författare)
-
N+CN→C+N2: A global potential energy surface, entrance channel recrossing and the applicability of capture theory
- 2011
-
Ingår i: Chem.Phys.Lett.. ; 514:1-3, s. 40-43
-
Tidskriftsartikel (refereegranskat)abstract
- A global potential energy surface for the system has been developed with the aim of studying the reaction at low temperatures. A three-dimensional analytic functional form has been fit to CASPT3/cc-pVQZ energies. Classical trajectory simulations on this fitted representation of the potential show a significant proportion of trajectories returning to the entrance channel after forming the intermediate, violating a key assumption of capture theory. While the fitted potential is considered inappropriate for calculating accurate low-temperature thermal rate constants, the potential can be used in future studies of the poorly characterised and reactions at temperatures relevant to combustion.
|
|
| 5. |
|
|
| 6. |
- Frankcombe, Terry J, et al.
(författare)
-
Statistical modelling of NH+/ND+ + H2/HD/D2 branching ratios.
- 2008
-
Ingår i: Physical chemistry chemical physics : PCCP. - : Royal Society of Chemistry (RSC). - 1463-9076 .- 1463-9084. ; 10:20, s. 3000-13
-
Tidskriftsartikel (refereegranskat)abstract
- In this work we study hydrogen isotope fractionation along the proposed gas-phase ammonia formation pathway at temperatures relevant to interstellar modelling. Specifically we study the isotopically substituted variants of the NH(+) + H(2) reaction, for which the primary product is NH(2)(+) + H. Adiabatic capture theory calculations have been performed for the association reaction. A new potential-energy surface has been determined for the NH(2)(+) product. An extensive set of rovibrational energy levels has been calculated for the NH(2)(+) isotopologues described by this potential-energy surface. These rovibrational energy levels have been used to determine energy- and angular-momentum-resolved numbers of accessible product states from the NH(3)(+) isotopologue intermediates, which in turn have been averaged to give statistical branching fractions for all isotopically-substituted NH(+) + H(2) reactions. It is determined that in all cases where both hydrogen and deuterium are present, the NHD(+) product is preferred.
|
|
| 7. |
- Reimers, Jeffrey R., et al.
(författare)
-
Challenges facing an understanding of the nature of low-energy excited states in photosynthesis
- 2016
-
Ingår i: Biochimica et Biophysica Acta - Bioenergetics. - : Elsevier BV. - 0005-2728 .- 1879-2650. ; 1857:9, s. 1627-1640
-
Forskningsöversikt (refereegranskat)abstract
- While the majority of the photochemical states and pathways related to the biological capture of solar energy are now well understood and provide paradigms for artificial device design, additional low-energy states have been discovered in many systems with obscure origins and significance. However, as low-energy states are naively expected to be critical to function, these observations pose important challenges. A review of known properties of low energy states covering eight photochemical systems, and options for their interpretation, are presented. A concerted experimental and theoretical research strategy is suggested and outlined, this being aimed at providing a fully comprehensive understanding.
|
|
