Slow photoelectron velocity-map imaging spectroscopy of the n-methylvinoxide anion

Abstract

High resolution photoelectron spectra of the n-methylvinoxide anion and its deuterated isotopologue are obtained by slow electron velocity-map imaging. Transitions between the X̃(1)A' anion ground electronic state and the radical X̃(2)A" and Ã(2)A' states are observed. The major features in the spectra are attributed to transitions involving the lower energy cis conformers of the anion and neutral, while the higher energy trans conformers contribute only a single small peak. Franck-Condon simulations of the X̃(2)A" ← X̃(1)A' and Ã(2)A' ← X̃(1)A' transitions are performed to assign vibrational structure in the spectrum and to aid in identifying peaks in the cis-n-methylvinoxy X̃ (2)A" band that occur only through vibronic coupling. The experimental electron affinity and à state term energy are found to be EA = 1.6106 ± 0.0008 eV and T(0) = 1.167 ± 0.002 eV for cis-n-methylvinoxy.

Nonadiabatic effects in substitutional isomers of Jahn-Teller molecules: The strange case of hydroxymethoxy

“…Recently, the emergence of accurate electron spectroscopies including the slow electron velocity-map imaging method 16 has raised questions concerning where in a spectrum nonadiabatic effects first appear. 34 The H d derived in this work, which is most accurate for low energies, will allow us to address this issue for hydroxymethoxy. The hydroxymethoxide photoelectron spectrum has not been experimentally measured but it is hoped that this and the future study will serve to motivate such an investigation.…”

Slow photoelectron velocity-map imaging spectroscopy of the C9H7 (indenyl) and C13H9 (fluorenyl) anions

“…Before installation of the cryogenic ion trap, typical linewidths of molecular systems were 15-30 cm −1 due to rotational broadening. [70][71][72] Even if there were no spectral congestion from vibrational hot bands and sequence bands, many of the features in the spectra would not have been resolved. For example, peak spacings between peaks L-M and M-N in fluorenyl are only 8 cm −1 and 12 cm −1 ; only peak N would have been apparent in our previous experimental configuration, with an unresolved shoulder at lower energy.…”

“…Similar effects of HT coupling on the PAD have been seen in previous photoelectron and SEVI spectra of C 2 H − and other anions. 72,86,87 One also might expect to see HT coupling with thẽ A 2 A 2 state, as this state lies only 1.26 eV above the ground state of fluorenyl. This coupling would activate vibrational modes of b 2 symmetry in the ground state spectrum, but no such modes are identified in Table II.…”

Intermolecular Vibrations in Hydrophobic Amino Acid Crystals: Experiments and Calculations

“…One way to use this information in a comparison is to project the eigenvectors of one calculation into the basis of eigenvectors from a second calculation. To some extent, the resulting matrix is similar to the Duschinsky rotation matrix J in the expression Q = JQ′ + K, 66 where Q and Q′ are the normal modes of a system in two different electronic states and K is a displacement vector. In this case, J is the transformation matrix that describes the linear combinations of vibrations needed to connect Q and Q′.…”