title: UV-photoexcitation and ultrafast dynamics of HCFC-132b (CF2 ClCH2 Cl).
abstract: The UV-induced photochemistry of HCFC-132b (CF2 ClCH2 Cl) was investigated by computing excited-state properties with time-dependent density functional theory (TDDFT), multiconfigurational second-order perturbation theory (CASPT2), and coupled cluster with singles, doubles, and perturbative triples (CCSD(T)). Excited states calculated with TDDFT show good agreement with CASPT2 and CCSD(T) results, correctly predicting the main excited-states properties. Simulations of ultrafast nonadiabatic dynamics in the gas phase were performed, taking into account 25 electronic states at TDDFT level starting in two different spectral windows (8.5 ± 0.25 and 10.0 ± 0.25 eV). Experimental data measured at 123.6 nm (10 eV) is in very good agreement with our simulations. The excited-state lifetimes are 106 and 191 fs for the 8.5 and 10.0 eV spectral windows, respectively. Internal conversion to the ground state occurred through several different reaction pathways with different products, where 2Cl, C-Cl bond breakage, and HCl are the main photochemical pathways in the low-excitation region, representing 95% of all processes. On the other hand, HCl, HF, and C-Cl bond breakage are the main reaction pathways in the higher excitation region, with 77% of the total yield. © 2015 Wiley Periodicals, Inc.
authors.affiliation: Universidade Federal da Paraiba, João Pessoa-PB, 58059-900, Brazil.|Max-Planck-Institut Für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an Der Ruhr, Germany.
authors.forename: Gessenildo Pereira
authors.initials: GP
authors.lastname: Rodrigues
authors.affiliation: Universidade Federal da Paraiba, João Pessoa-PB, 58059-900, Brazil.
authors.forename: Elizete
authors.initials: E
authors.lastname: Ventura
authors.affiliation: Universidade Federal da Paraiba, João Pessoa-PB, 58059-900, Brazil.
authors.forename: Silmar
authors.initials: S
authors.lastname: Andrade do Monte
authors.affiliation: Max-Planck-Institut Für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an Der Ruhr, Germany.|Aix Marseille Université, CNRS, ICR UMR7273, 13397, Marseille, France.
authors.forename: Mario
authors.initials: M
authors.lastname: Barbatti
keywords: HCFC; atmospheric photochemistry; excited states; nonadiabatic dynamics; photochemistry; photodissociation; surface hopping