Nonadiabatic Quantum Dynamics Predissociation of H₂O⁺(B̃ ²B₂)

Abstract

El acceso a la versión del editor puede requerir la suscripción del recurso E-mail: ismanuel.rabadan@uam.esAbstract A quantum-mechanical study of the predissociation of H 2 O + (B 2 B 2 ) is carried out by using wave packet propagations on ab initio potential energy surfaces connected by nonadiabatic couplings. The simulations show that within the first 30 fs, 80% of the initial wave packet is transferred from theB 2 B 2 to theà 2 A 1 electronic state through a conical intersection. A much slower transfer (in the ps timescale) from theà 2 A 1 to thẽ X 2 B 1 state due to a Renner-Teller coupling determines the fragmentation branching ratios, which are in accordance with the experimental measurements.

Theoretical study of the mechanism ofH2O+dissociative recombination

“…As a function of the angle, the potential energy surfaces of the resonant states show clear indications of conical intersections. Similar conical intersections are found among the potential energy surfaces of excited ionic states [25]. Since the resonant states are Rydberg states that converge to the excited ionic cores, the same behavior of the potentials are found for the resonant states.…”

Born–Oppenheimer and Renner–Teller coupled-channel quantum reaction dynamics of O(3P) + H2+(X2Σg+) collisions

“…The product channels (1.1) and (1.2) are uncoupled within the adiabatic Born-Oppenheimer (BO) approximation and occur, respectively, on the two lowest X 2 A 00 and à 2 A 0 PESs of OH 2 + , which transform as 2 B 1 and 2 A 1 , respectively, in C 2v symmetry. 13. These two electronic states of H 2 O + correspond to the degenerate components of a 2 P u species, when the molecule is in a linear arrangement, and the associated nonadiabatic (NA) Renner-Teller (RT) effects can remarkably influence the dynamics of these collisions, as they also occur for the X 2 B 1 À à 2 A 1 optical spectrum 12 of H 2 + O.…”

Lattice description of electron loss in high-energy H++H2O collisions

“…1b 1 is the HOMO orbital, essentially a non-bonding 2p y orbital of the oxygen atom, perpendicular to the molecular plane, while the electron occupying the 1b 2 orbital is delocalized between the oxygen and hydrogen atoms, and its removal leads to the formation of H 2 O + (B 2 B 2 ), which readily predissociates following the mechanism recently described in Ref. [34].…”

“…To our knowledge, lattice methods have not been applied to ion-molecule collisions. Our treatment is based on the GridTDSE [33] parallel computational package that we have recently applied to study the predissociation of the water cation [34]. In addition to the calculation of electron transition probabilities, the numerical integration of the TDSE provides a direct visualization of the electronic dynamics.…”