We apply molecular beam time-of-flight mass spectrometry in conjunction with (1) one-color resonant two-photon ionization (1C-R2PI), (2) two-color resonant two-photon ionization (2C-R2PI), and (3) mass-analyzed threshold ionization (MATI, also referred as mass-analyzed zero kinetic energy photoelectron) spectroscopy to study the properties of molecules, complexes and clusters in the electronically excited and cationic states. The experimental data obtained from these spectra include the origin of electronic transition, adiabatic ionization energy, vibrational frequency, intermolecular binding energy, etc. These yield information about electronic transition, ionization threshold, vibration, structure, bonding and dynamics, etc. We also perform ab initio and density functional theory (DFT) calculations to provide possible interpretation for the experimental findings.

References:

1. J. L. Lin andW. B. Tzeng, “Mass analyzed threshold ionization of deuterium substituted isotopomers of aniline and p-fluoroaniline: Isotope effect and site-specific electronic transition”, J. Chem. Phys. 115, 743-751 (2001). 
2. J. L. Lin, L. C. L. Huang, and W. B. Tzeng“Mass analyzed threshold ionization spectroscopy of the selected rotamers of hydroquinone and p-dimethoxybenzene cations”, J. Phys. Chem. A 105, 11455-11461 (2001).
3. J. L. Lin, K. C. Lin, and W. B. Tzeng, “Mass analyzed threshold ionization spectroscopy of o-, m-, and p-methylaniline: Vicinal substitution effects on electronic transition, ionization, and molecular vibration”, J. Phys. Chem. A 106, 6462-6468 (2002).