Fragmentation energetics of the phenol(+)···Ar(3) cation cluster.
The various dissociation thresholds of phenol(+)···Ar(3) complexes for the consecutive loss of all three Ar ligands were measured in a molecular beam using resonant photoionization efficiency and mass analyzed threshold ionization spectroscopy via excitation of the first excited singlet state (S(1)). The adiabatic ionization energy is derived as 68077 ± 15 cm(-1). The analysis of the dissociation thresholds demonstrate that all three Ar ligands in the neutral phenol···Ar(3) tetramer are attached to the aromatic ring via π-bonding, denoted phenol···Ar(3)(3π). The value of the dissociation threshold for the loss of one Ar ligand from phenol(+)···Ar(3)(3π), ∼190 cm(-1), is significantly lower than the binding energy measured for the π-bonded Ar ligand in the phenol(+)···Ar(π) dimer, D(0) = 535 ± 3 cm(-1). This difference is rationalized by an ionization-induced π → H isomerization process occurring prior to dissociation, that is, one Ar atom in phenol(+)···Ar(3)(3π) moves to the OH binding site, leading to a structure with one H-bonded and 2 π-bonded ligands, denoted phenol(+)···Ar(3)(H/2π). The dissociation thresholds for the loss of two and three Ar atoms are also reported as 860 and 1730 cm(-1). From these values, the binding energy of the H-bound Ar atom can be estimated as 870 cm(-1).
Armentano
Antonio
A
Photon Science Institute, The University of Manchester, Manchester, M13 9PL, United Kingdom.
Riese
Mikko
M
Taherkhani
Mehran
M
Ben Yezzar
Med
M
Müller-Dethlefs
Klaus
K
Fujii
Masaaki
M
Dopfer
Otto
O
D001128:Argon / Q000737:chemistry*; D002412:Cations / Q000737:chemistry; D008024:Ligands; D010636:Phenols / Q000737:chemistry*; D011789:Quantum Theory
D002412:Cations; D008024:Ligands; D010636:Phenols; D001128:Argon