Double ionization of quaterrylene (C40H20) in water-ice at 20 K with Ly alpha (121.6 nm) radiation.
J Phys Chem A
; 110(28): 9020-4, 2006 Jul 20.
Article
en En
| MEDLINE
| ID: mdl-16836467
ABSTRACT
Polycyclic aromatic hydrocarbon (PAH) molecules undergo facile ionization in cryogenic water-ices resulting in near quantitative conversions of neutral molecules to the corresponding singly charged radical cations. Here we report, for the first time, the production and stabilization of a doubly ionized, closed shell PAH in water-ice. The large PAH quaterrylene (QTR, C40H20) is readily photoionized and stabilized as QTR 2+ in a water-ice matrix at 20 K. The kinetic analysis of photolysis shows that the QTR 2+ is formed at the expense of QTR +, not directly from QTR. The long-axis polarized S1-S0 (1(1)B(3u) <-- 1(1)Ag) transition for QTR 2+ falls at 1.59 eV (782 nm). TD-DFT calculations at the B3LYP level predict that this transition falls at 1.85 eV (670 nm) for free gas-phase QTR 2+, within the 0.3 eV uncertainty associated with these calculations. This red shift of 0.26 eV is quite similar to the 0.24 eV red shift between the TD-DFT computational prediction for the lowest energy transition for QTR + (1.68 eV) and its value in a water matrix (1.44 eV). These results suggest that multiple photoionization of such large PAHs in water-ice can be an efficient process in general.
Buscar en Google
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Hidrocarburos Policíclicos Aromáticos
Tipo de estudio:
Prognostic_studies
Idioma:
En
Revista:
J Phys Chem A
Asunto de la revista:
QUIMICA
Año:
2006
Tipo del documento:
Article
País de afiliación:
Estados Unidos