Potential energy surfaces and properties of ICN and ICN



ICN and ICN have been studied at the MR-SO-CISD level of theory with triple-zeta basis sets for all three atoms. The potential surfaces for the ground states of ICN and ICN as well as for the first five excited states of ICN have been generated from the electronic energies, and properties of these states are described. The minimum energy geometry of ICN is linear, with a local minimum in the INC geometry. The zero-point corrected energy difference between these two isomers is 0.38 eV, and they are separated by a 0.5 eV barrier. The I···CN(COM) equilibrium distances are 3.27 and 3.14 Å in the ICN and INC geometries, respectively. These values are 0.6 Å larger than the I···CN distances in the corresponding minima in the ICN potential. Likewise, the zero-point amplitude of both the I···CN stretch and bend are much larger in ICN than in ICN. This is captured by the calculated anharmonic fundamental frequencies for ICN of 70 and 235 cm−1 for the bend and stretch, compared to anharmonic frequencies of 302 and 488 cm−1 for the bend and stretch fundamentals in ICN. The frequencies are lowered further in INC where the bend and stretch fundamentals have frequencies of 59 and 220 cm−1. © 2012 Wiley Periodicals, Inc.