One-color two-photon mass-analyzed threshold ionization has been applied to 2-bromopropane (2-BP). The adiabatic ionization potential energies for the two spin states of this molecule are determined to be 81403 +/- 5 and 83 399 +/- 5 cm(-1), respectively. A few characteristic vibrations of the 2-BP cation are observed and assigned, which are mainly related to the C-Br stretching and CH3 motions. The C-Br bond is weakened due to the large lengthening of C-Br bond in the cationic state relative to the ground state of the neutral. These results are well supported by our theoretical calculations. (c) 2005 Elsevier B.V. All rights reserved.