POTENTIAL ENERGY SURFACES AND DYNAMICS OF THE EXCITED OH(A2Σ+) IN COLLISIONS WITH HE AND CO(X1Σ+)

Abstract

THE AIM OF THE WORK WAS THE THEORETICAL STUDY OF THE DYNAMICAL BEHAVIOUR OF THEEXCITED OH(A2Σ+) IN COLLISIONS WITH HE AND CO. AB INITION POTENTIAL CURVES OF HEO AND POTENTIAL ENERGY SURFACES OF HEOH FOR THE FIRST THREE STATES WERE CALCULATED. AN ANALYTICAL POTENTIAL FUNCTION FOR THE EXCITED 22A' STATE WAS PRODUCED AND CLOSE-COUPLING SPIN AVERAGED TOTAL CROSS SECTIONS WERE CALCULATED.IT WAS FOUND THAT EVEN ROTATIONAL TRANSITIONS ARE FAVOURED OVER THE ODE ONES. THE COMPUTED PARTIAL CROSS SECTIONS SHOWED SECONDARY MINIMA AND EXPLANATION WAS THOUGHT BY EXAMING THE APPROPRIATE CLASSICAL TRAJECTORIES. THESE FEATURES WERE ATTRIBUTED TO MULTIPLE COLLISION EFFECTS IN THE ELECTRONIC DEEXITATION OF OH(A2Σ+) IN COLLISIONS WITH GROUND STATE CO WAS STUDIED. THE CALCULATIONS CONFIRM THE EXPERIMENTALLY DEDUCED PICTURE OF A COLLISION COMPLEX FORMATION AND THUS THE DEPENDENCE OF THE QUENCHING CROSS SECTION ON THE ROTATIONAL EXCITATION OF OH(A2Σ+) AND THE COLLISION TEMPERATURE. THE STUDY OF THE DYNAMICAL BEHAVIOUR OF THE EXCITED OH WITH HE, BY RUNNING CLASSICAL TRAJECTORIES REVEALEDTHAT THE MOST IMPORTANT PATH OF THE QUENCHING IS THROUGH THE FORMATION OF THE C2V SYMMETRY COMPLEX.