INSTITUTO DE QUIMICA, FISICA DE LOS MATERIALES, MEDIOAMBIENTE Y ENERGIA
Unidad Ejecutora - UE
Biradicalic excited states of zwitterionic phenol-ammonia clusters
A. CARRERA, I. B. NIELSEN, P. CARCABAL, C. DEDONDER, M. BROQUIER, C. JOUVET, W. DOMCKE, A. L. SOBOLEWSKI
JOURNAL OF CHEMICAL PHYSICS
AMER INST PHYSICS
Año: 2009 vol. 130 p. 24302 - 24302
Phenol-ammonia clusters with more than 5 ammonia molecules are proton-transferred species in the ground state. In the present work, the excited states of these zwitterionic clusters have been studied experimentally with two color pump probe methods on the nanosecond time scale and by ab initio electronic-structure calculations. The experiments reveal the existence of a long-lived excited electronic state with a lifetime in the 50-100 ns range, much longer than the excited-state lifetime of bare phenol and small clusters of phenol with ammonia. The ab initio calculations indicate that this long-lived excited state corresponds to a biradicalic system, consisting of a phenoxy radical which is hydrogen-bonded to a hydrogenated ammonia cluster. The biradical is formed from the locally excited state of the phenolate anion via an electron transfer process which neutralizes the charge separation of the ground-state zwitterion.