A Theoretical Study on the Excited States of the KCCH Radical

¹ College of Science, Jiamusi University, 154007 Jiamusi, China
² School of Nursing, Yanbian University, 13300 Yanji, China

^* Corresponding author: peiweiwei50082@126.com; 1961372847@qq.com; 544382415@qq.com

Abstract

Based on the C_2v symmetry, the low-lying electronic states of the KCCH radical was studied in the complete active pace self-consistent field (CASSCF) and multi-configurational second-order perturbation theory (CASPT2) methods. For the low-lying electronic states of KCCH, the calculated harmonic vibrational modes are in agreement with theoretical reports. Moreover, the electron transitions of KCCH, from X¹Σ⁺ to 2¹Σ⁺, 1¹Π, 2¹Π, 1¹Σ^-, 1³Σ⁺, 1³Π, 2³Π and 1³Σ^-, are predicted at 5.43, 5.59, 7.87, 5.50, 5.15, 5.73, 5.53 and 6.82 eV, respectively. The CASSCF/CASPT2 potential energy curves (PECs) were calculated for K⁺-loss dissociation from the 1³Σ⁺, 2³Σ⁺,1³Π ,2¹Σ, 1¹Π and 2¹Π states. Analyses of electron transition and dissociation curves show the ionic properties in the metal–ligand bond for KCCH. The dissociation energy of the KCCH (X¹Σ⁺)→CCH-(1¹Σ)+K⁺(S⁰) is 4.423 eV at the CASSCF/CASPT2 level.