H2 O2 +Ng Excited Electronic State Description

Abstract

IntroductionHydrogen peroxide (H 2 O 2 ) plays an important role in several chemical and physical processes, evidenced in astronomy, medicine, and chemical reactions. Due its importance and diversity of applications, this molecule has been subject of several studies 1,2 . Recently, our research group has developed an analytical interpretation of noble-gases influence on hydrogen peroxide by means of a potential energy surface that involves angular and radial coordinates of noble gases. The Improved Lennard Jones (ILJ) analytical form 2 , widely applied in this kind of systems, was used in order to represent the Van der Waals interaction of noble gas and O-H bound. In this work, we present the H 2 O 2 -Ng (with Ng=He,Ne, Ar, and Kr) potential energy curves (PEC) in the excited electronic states. Furthermore, these new PEC are exploited to describe the dynamical properties (rovibrational energies and spectroscopic constants) of the H 2 O 2 -Ng systems. Methods and DiscussionIt is large known that the study of excited states is not an easy task. It request a long computational simulation time and depending on electrons quantity it may be not viable. Considering this facts, it becomes crucial cost-benefits considerations. By these assumptions, we considered H 2 O 2 + He, H 2 O 2 + Ne, H 2 O 2 + Ar, H 2 O 2 + Kr on equilibrium geometries given by Table below (geometrical definition are shown in Figure 1). Artigo Geral 66Figure 1: H 2 O 2 -Ng geometrical representation. (a) R s the distance from noble-gas and center of O-O bond. (b) θ1 and θ2 are the angles between O-H bond and y axis. Jul / Dez de 2015 Edição Especial XVIII SBQT Revista Processos Químicos 267For all complexes, we calculated the electronic energies as a function of R (from 3Å to 10Å, with 0,2Å of step) considering 15 excited states. All these calculations were performed using the TDDFT method (implemented in the NWCHEM code3), with the camqtp-00 functional and the aug-cc-pVTZ basis set. These excited electronic energies were adjusted by generalized rydberg functions, as shown in Figure 2. Then, these analytical PEC were used to determine the rovibrational energies and spectroscopic constants. for all studied systems. These properties were calculated by two different methods: Solving the nuclear Schrodinger's equation (by Discrete Variable Representation 4) and Dunham 5 method. The results obtained through Dunham and DVR methodologies are in an excellent agreement. This fact demonstrates the reliability of our study. ConclusionsIn this work, we have presented a study of the interaction among the H 2 O 2 molecule with noblegases (He, Ne, Ar, and Kr) on the excited electronic states. Analytical PEC, ro-vibrational energies and spectroscopic constants were determined considering fifteen electronic states for each system. These kind of results represent the main novelty of this work, since they are presented for first time in the literature.