The S1←S0 000 transitions of phenol and the hydrogen bonded phenol(H2O)1 cluster have been studied by high resolution fluorescence excitation spectroscopy. All lines in the monomer spectrum are split by 56±4 MHz due to the internal rotation of the −OH group about the a axis. The barrier for this internal motion is determined in the ground and excited states; V2″=1215 cm−1, and V2′=4710 cm−1. The rotational constants for the monomer in the ground state are in agreement with those reported in microwave studies. The excited state rotational constants were found to be A′=5313.7 MHz, B′=2620.5 MHz, and C′=1756.08 MHz. The region of the redshifted 000 transition of phenol(H2O)1 shows two distinct bands which are 0.85 cm−1 apart. Their splitting arises from a torsional motion which interchanges the two equivalent H atoms in the H2O moiety of the cluster. This assignment was confirmed by spin statistical considerations. Both bands could be fit to rigid rotor Hamiltonians. Due to the interaction between the overal...

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High resolution uv spectroscopy of phenol and the hydrogen bonded phenol/water cluster

This is the third of a series of articles reporting critically evaluated rotational–vibrational line positions, transition intensities, and energy levels, with associated critically reviewed labels and uncertainties, for all the main isotopologues of water. This paper presents experimental line positions, experimental-quality energy levels, and validated labels for rotational–vibrational transitions of the most abundant isotopologue of water, H216O. The latest version of the MARVEL (Measured Active Rotational–Vibrational Energy Levels) line-inversion procedure is used to determine the rovibrational energy levels of the electronic ground state of H216O from experimentally measured lines, together with their self-consistent uncertainties, for the spectral region up to the first dissociation limit. The spectroscopic network of H216O containstwo components, an ortho (o) and a para (p) one. For o-H216O and p-H216O, experimentally measured, assigned, and labeled transitions were analyzed from more than 100 sources. The measured lines come from one-photon spectra recorded at room temperature in absorption, from hot samples with temperatures up to 3000 K recorded in emission, and from multiresonance excitation spectra which sample levels up to dissociation. The total number of transitions considered is 184 667 of which 182 156 are validated: 68 027 between para states and 114 129 ortho ones. These transitions give rise to 18 486 validated energy levels, of which 10 446 and 8040 belong to o-H216O and p-H216O, respectively. The energy levels, including their labeling with approximate normal-mode and rigid-rotor quantum numbers, have been checked against ones determined from accurate variational nuclear motion computations employing exact kinetic energy operators as well as against previous compilations of energy levels. The extensive list of MARVEL lines and levels obtained are deposited in the supplementary data of this paper, as well as in a distributed information system applied to water, W@DIS, where they can easily be retrieved.

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IUPAC critical evaluation of the rotational-vibrational spectra of water vapor, Part III: Energy levels and transition wavenumbers for H216O

This is the first part of a series of articles reporting critically evaluated rotational– vibrational line positions, transition intensities, pressure dependence and energy levels, with associated critically reviewed assignments and uncertainties, for all the main isotopologues of water. The present article contains energy levels and data for line positions of the singly substituted isotopologues H2

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IUPAC critical evaluation of the rotational-vibrational spectra of water vapor. Part I—Energy levels and transition wavenumbers

The first spectra of the A 2Π3/2 ← X 2Π3/2 electronic transition of BrO using Fourier transform ultraviolet spectroscopy are obtained. Broadband vibrational spectra acquired at 298 ± 2 K and 228 ± ...

Fourier Transform Ultraviolet Spectroscopy of the A 2Π3/2 ← X 2Π3/2 Transition of BrO†

Resonant two‐photon ionization spectroscopy has been applied to the jet‐cooled Au2 and AgAu molecules. Three new band systems of Au2 and two new systems of the poorly characterized AgAu molecule have been observed. Excited state lifetime measurements have been made, and assignments of the excited states are suggested. For Au2 the a 3Σ+1u←X 1Σ+g transition has been detected, and vibrational levels of the a 3Σ+1u state have been observed up to v’=33, which lies only 120 cm−1 below the convergence limit of the system. This allows a precise confirmation of previous high temperature Knudsen effusion measurements of the bond strength of Au2 as D00(Au2)=2.290±0.008 eV. In addition, the excited states of Au2 of 0+u symmetry are shown to have significantly shorter fluorescence lifetimes than the 1u states, and this is explained as resulting from an admixture of Au+Au− ion pair character in these Ω’=0+u states. The ionization potential of Au2 has been bracketed as IP(Au2)=9.20±0.21 eV, which may be combined with th...

Spectroscopic studies of jet‐cooled AgAu and Au2

/pdf/absolute-iodine-i2-standards-measured-by-means-of-fourier-37870tvo7j.pdf

S. Gerstenkorn

Papers

Absolute iodine (I2) standards measured by means of Fourier transform spectroscopy