THEORETICAL-STUDY OF THE ELECTRONIC AND GEOMETRICAL STRUCTURE OF THE GROUND AND LOW-LYING STATES OF NCL2, PCL2, NCL, AND PCL RADICALS

Using a variety of ab initio methods, SCF, CISD, MP2, MP4, MCSCF, and MCSCF+1+2, we have studied the electronic and geometical structure of the ground and low-lying states of the isovalent radicals NCl2, PCl2 a nd NCl, PCl. In particular, we have examined the states ($) over tilde X(2)B(1), ($) over tilde A(2)A(1), ($) over tilde (BB2)-B-2, ($) over tilde C(2)A(1), ($) over tilde D(2)A(2) and ($) over tilde X(2)B(1), ($) over tilde A(2)A(1), ($) over tilde (BB2)-B-2, ($) over tilde C(2) A(1), ($) over tilde (DB2)-B-2, ($) over tilde E(2)A(2) for NCl2 and P Cl2, respectively. These calculated manifolds can be proved useful in elucidating the complicated electronic spectroscopy of the triatomic s pecies. For the diatomic molecules we have examined the states X(3) Si gma(-), a(1) Delta, and b(1) Sigma(+), while, for the ground X(3) Sigm a(-) state only, we constructed full energy potential curves in an eff ort to obtain accurate dissociation energies.