Dynamics of electron attachment and photodissociation in iodide-uracil-water clusters via time-resolved photoelectron imaging.
J Chem Phys
; 149(8): 084301, 2018 Aug 28.
Article
em En
| MEDLINE
| ID: mdl-30193511
ABSTRACT
The dynamics of low energy electron attachment to monohydrated uracil are investigated using time-resolved photoelectron imaging to excite and probe iodide-uracil-water (I-·U·H2O) clusters. Upon photoexcitation of I-·U·H2O at 4.38 eV, near the measured cluster vertical detachment energy of 4.40 eV ± 0.05 eV, formation of both the dipole bound (DB) anion and valence bound (VB) anion of I-·U·H2O is observed and characterized using a probe photon energy of 1.58 eV. The measured binding energies for both anions are larger than those of the non-hydrated iodide-uracil (I-·U) counterparts, indicating that the presence of water stabilizes the transient negative ions. The VB anion exhibits a somewhat delayed 400 fs rise when compared to I-·U, suggesting that partial conversion of the DB anion to form the VB anion at early times is promoted by the water molecule. At a higher probe photon energy, 3.14 eV, I- re-formation is measured to be the major photodissociation channel. This product exhibits a bi-exponential rise; it is likely that the fast component arises from DB anion decay by internal conversion to the anion ground state followed by dissociation to I-, and the slow component arises from internal conversion of the VB anion.
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1
Coleções:
01-internacional
Base de dados:
MEDLINE
Idioma:
En
Revista:
J Chem Phys
Ano de publicação:
2018
Tipo de documento:
Article
País de afiliação:
Estados Unidos