Rotamers of p-methoxyphenol cation studied by mass analyzed threshold ionization spectroscopy

The adiabatic ionization energies of cis and trans p-methoxylphenol have been determined to be 62 313 ± 5 and 62 210 ± 5 cm−1, respectively. The frequencies of vibrations 9b, 6a, and 1 are measured to be 426, 519, and 830 cm−1 for the cis and 425, 518, and 831 cm−1 for the trans conformer of the p-methoxyphenol cation. This indicates that the influence of different orientation of the OH and OCH3 groups on these active in-plane vibrations is insignificant.