Zero-kinetic-energy photoelectron spectroscopy of the hydrogen-bonded phenol-water complex

Abstract

Two-photon, two-color (1+1′) zero-kinetic-energy (ZEKE) photoelectron spectra are presented for the 1:1 phenol-water complex, a prototype system for hydrogen bonding between an aromatic molecule and a simple solvent. ZEKE spectra via different (intermolecular) vibrational intermediate S1 levels of the fully protonated complex (C6H5OH–H2O, h3) as well as the ZEKE spectrum via the vibrationless S1 state of the threefold deuterated complex (C6H5OD–D2O, d3) have been recorded. The spectra are rich in structure, which is mainly attributable to intermolecular vibrations of the ionic complex. Progressions of the intermolecular stretch vibration (240 cm−1) in combination with different intermolecular and intramolecular vibrational levels are the dominant feature of all ZEKE spectra obtained and indicate a large change in the complex geometry along the hydrogen-bond coordinate on ionization. Comparison between the spectrum of the d3 complex and the spectra via different intermediate intermolecular levels of the h3 complex has allowed a more detailed analysis of the intermolecular features compared to previously reported results. Finally, the vibrational assignments obtained are compared with ab initio results for the phenol-water cation reported in the following paper in this issue.

Structures and IR/UV spectra of neutral and ionic phenol–Arn cluster isomers (n≤ 4): competition between hydrogen bonding and stacking

“…Similar to DS 1 , the DIP shifts induced by Ar complexation directly reflect the change in the intermolecular interaction energy upon ionisation. The experimental IP of PhOH (68 628 cm À1 ) 63 is well reproduced (to within 0.3%) by the M06-2X calculations (68 426 cm À1 ), indicating that this level is adequate to describe the ionisation process of the bare aromatic molecule by removal of the p electron from the HOMO.…”

Photoionization-induced large-amplitude pendular motion in phenol+–Kr

“…First, there are only few intramolecular modes of phenol + with frequencies lower than 500 cm À1 , namely n 11 = 177, n 16a = 348, n 18b = 411, and n 16b = 428 cm À1 . 23 Second, as all three intermolecular modes of phenol + -Kr are involved in the reaction coordinate, they cannot act as bath modes. The low density of bath states results in small IVR rates, which enables the efficient H -p back reaction in phenol + -Kr.…”

Communication: The ionization spectroscopy of mixed carboxylic acid dimers

“…The measured small IP redshift of 545 cm −1 from monomer to its formic acid dimer is particularly interesting compared to other systems such as the single H bonded phenol-H 2 O and indole-H 2 O clusters in which the IP redshifts are several thousands of wavenumbers. 10 Our results show that the MATI spectroscopy is well suited to study certain kinds of multiple H bonded clusters. These complexes possess two intermolecular H bonds in addition to the intra H bond already present in the monomer.…”