suitable to describe complex chemical reactions in condensed phase. The parametric forms of S and Z as a function of the configurational space vectors X are given in equations 1 and 2. In this work, the components of vector X are: 1) the C-N coordination number, 2) O-H coordination number and 3) the N * -H coordination number, with N * the N closest to CO 2 's C atom (see definition below). The combination of these 3 variables uniquely defines the 4 chemical states of interest in this work, as shown by the 4 separate wells in Fig. .