The vacuum-ultraviolet (VUV) pulsed-field ionization-photoelectron (VUV-PFI-PE) spectra of trans-1-bromopropene (trans-CH3CH=CHBr) and cis-1-bromopropene (cis-CH3CH=CHBr) have been measured in the energy region of 74 720-76 840 cm(-1). The simulation of fine structures observed in the origin VUV-PFI-PE vibrational bands of these molecules has provided the ionization energies (IEs) of trans-1-bromopropene and cis-1-bromopropene to be 74 779.3+/-2.0 cm(-1) (9.2715+/-0.0002 eV) and 75 140.2+/-2.0 cm(-1) (9.3162+/-0.0002 eV), respectively. The vibrational bands resolved in these VUV-PFI-PE spectra at energies 0-1700 cm-1 above the IEs of trans-1-bromopropene and cis-1-bromopropene have been assigned based on theoretical vibrational frequencies and calculated Franck-Condon factors for the ionization transitions. (C) 2004 American Institute of Physics.