Theoretical study of the C3Cl radical and its cation

A theoretical study of C3Cl and C3Cl+ isomers has been carried out. The glo bal minimum for C3Cl is a cyclic C-2v species (a three-membered ring with a n exocyclic chlorine atom). However, a quasi-linear CCCCl structure is pred icted to lie only 3-5 kcal mol(-1) higher. This quasi-linear structure is f loppy, since the linear arrangement lies only 2-3 kcal mol(-1) higher in en ergy. The cyclic and open-chain isomers have dipole moments of 1.986 and 3. 363 D, respectively. In C3Cl+ the global minimum is a linear singlet specie s, the singlet cyclic isomer lying about 19 kcal mol(-1) higher. The ioniza tion potentials of cyclic and open-chain C3Cl are estimated to be 9.17 and 8.21 eV, respectively, suggesting that these species should be easily ioniz ed if present in the interstellar medium. (C) 1999 Elsevier Science B.V. Al l rights reserved.