The vacuum ultraviolet (VUV) pulsed field ionization-photoelectron (PFI-PE) spectrum for transdichloroethene (trans-CICH=CHCl) has been measured in the energy range 77 600-79 200 cm(-1). On the basis of the spectral simulation of the origin VUV-PFI-PE vibrational band, we have determined the IE(trans-CICH=CHCI) to be 77 678.4 +/- 2.0 cm(-1) (9.630 97 +/- 0.000 25 eV). The vibrational bands resolved in the VUV-PFI-PE spectrum of trans-CICH=CHCI are assigned on the basis of ab initio vibrational frequencies and calculated Franck-Condon factors for the ionization transitions, yielding eight vibrational frequencies nu(1)(+) = 163 cm(-1), nu(3)(+) = 367 cm(-1), nu(4)(+) = 871 cm(-1), nu(5)(+) = 915 cm(-1), nu(6)(+) = 944 cm(-1), nu(8)(+) = 1235 cm(-1), nu(9)(+) = 1258 cm(-1), nu(10)(+) = 1452 cm(-1). The distinct feature of the VUV-PFI-PE spectrum is the strong vibrational progression of the V-3(+) (C-Cl stretching) mode of trans-ClCH=CHCl+, which is consistent with the theoretical geometry calculation, predicting a significant change in the C-Cl bond distance upon photoionization of trans-ClCH=CHCl. We have also determined the frequency (3068 cm(-1)) for the nu(11)(+) (C-H stretching) vibrational mode of trans-ClCH=CHCl+ by employing the VUV-IR-photoinduced Rydberg ionization (VUV-IR-PIRI) method. The VUV-IR-PIRI spectra for trans-CICH=CHCI prepared in the effective principal quantum numbers, n* = 14 and 36, are found to be identical, supporting the previous conclusion that the Rydberg electron behaves as a spectator; i.e., the Rydberg electron orbital is conserved during the IR excitation of the ion core.