Potential energy surfaces of NaFH

Abstract

High-level ab initio calculations of the ground and several excited-state adiabatic potential surfaces of the NaFH system are reported. These calculations were performed by multireference configuration interaction on a large grid of geometries which allowed them to be used for constructing an accurate analytic representation of the NaFH potential surfaces. For the ground and first excited states, using a genetic algorithm, an analytic 2×2 matrix fit was obtained corresponding to a diabatic representation. The off-diagonal coupling was obtained by fitting the energy gap between the surfaces in the region of their avoided crossing, and the diagonal elements were then fit to reproduce the ab initio adiabatic energy at 1530 points. The full fit was used to locate the barrier and the van der Waals well on the ground-state potential surface, the exciplex on the first-excited-state potential surface, and the minimum energy path for the ground-state Na+HF→NaF+H reaction. Additional calculations on the van der Waals and saddle point regions were carried out by a variety of ab initio methods as a check on accuracy. Major topological features of the potential energy surfaces representing higher-than-first excited states were examined.

Transition State Spectroscopy of the Photoinduced Ca + CH3F Reaction. 1. A Cluster Isolated Chemical Reaction Study

“…Something new happens in the latter system that does not seem relevant of the local excitation that prevails in the Ca · · · HBr experiment. This is very unexpected not only because of the present comparison with the Ca · · · HBr system but also because local excitation of the metal moiety prevails in all the apparently similar complexes that were investigated so far: complexes between an alkali atom and halogen containing molecules [12,[42][43][44][45][46][47][48][49] or a complex between barium and CH 3 F [15,19,23,25]. Local excitation has also been found in many excited metal ion complexes such as Mg + CH 3 I described in Ref.…”

Transition State Spectroscopy of the Photoinduced Ca + CH3F Reaction. 2. Experimental and Ab Initio Studies of the Free Ca···FCH3 Complex

“…In particular the Na/HF system has benefited of extensive ab initio energetics and transition dipole moment calculations that yielded an action spectrum in good agreement with the experimental data [35,36].…”

“…Potential and dynamical calculations are also available, essentially for alkali/hydrogen halide systems [9,28,29,30,31,32,33,34,35,36]. In particular the Na/HF system has benefited of extensive ab initio energetics and transition dipole moment calculations that yielded an action spectrum in good agreement with the experimental data [35,36].…”

Quantum stereodynamics of the Li+HF(v,j) reactive collision for different initial states of the reagent

“…In fact, the experimental detection of the products in the photoinitiated reaction of Li-HF presents some disadvantages since this system reacts at thermal energies. However, other related systems like Na-HF [20][21][22] and Ca-HF 42 candidates for such experiments on the ground electronic state.…”

“…Nowadays, there is an increasing number of theoretical works on these systems [15][16][17][18][19][20] due to the development of the methodology to describe the reaction dynamics of three atoms systems and to the appearance of accurate global potential energy surfaces ͑GPES͒ for some of these systems like LiϩHF 16,19 or NaϩHF. [20][21][22] Another source of valuable information is the reaction dynamics dependence on the relative velocity vectors between reactants and products and on the angular momenta involved in the process. This means that it is necessary to create and register the relative orientation of the different vector properties involved in a reactive collision, and their mutual correlations, to get a deeper insight about the reaction dynamics.…”