The stepwise and concerted dissociation of ground state molecule under external fields is studied for the first time with density functional theory. The geometry, the orbit energies, the dissociation properties and the IR spectrum of CF2Br2 under external electrical fields (-0.015 a. u. to 0.065 a. u.) have been calculated at the B3PW91/6-311+ G (2df) level. The potential energy surfaces along single and two C-Br bonds under different external fields were obtained which indicate that the stepwise dissociation will happen under 0.055 a. u. and a generally repulsive pathway towards the concerted dissociation of ground state CF2Br2 exists under 0.065 a. u.(1 a. u. = 5.14225 x 10(11) V.m(-1)). (C) 2018 Elsevier B.V. All rights reserved.