ZEKE-PFI spectroscopy of benzocaine

J Phys Chem A. 2006 May 11;110(18):6010-5. doi: 10.1021/jp0582944.

Abstract

The adiabatic ionization threshold (AIT) of trans- and gauche-benzocaine has been measured by zero electron kinetic energy-pulsed field ionization (ZEKE-PFI) spectroscopy to be 7.8412+/-0.0008 eV (lasers at 34,134.4 and 29,109.3 cm(-1)) and 7.8421+/-0.0004 eV (34,144.8+29105.7 cm(-1)), respectively. AITs computed at the B3LYP/AUG-cc-p-VDZ level for the two conformers are some approximately 2,500 cm(-1) lower than the experimental; in contrast their energy difference is very close. The trans-benzocaine cation ZEKE spectra has been recorded taking a number of S(1) intermediate vibronic states. The spectra provide an energy threshold for the appearance of intramolecular vibrational redistribution (IVR) around approximately 540 cm(-1) in the S(1) state.