MAGNETIC-FIELD-INDUCED ALIGNMENT-ORIENTATION CONVERSION - NONLINEAR ENERGY SHIFT AND PREDISSOCIATION IN TE-2 B1(U) STATE

The paper analyzes magnetic field induced alignment-orientation conver sion (AOC) phenomenon caused by simultaneous effect of quadratic terms in Zeeman energy shift and magnetic predissociation (PD), producing a symmetry either in energy splitting omega(MM+/-1)not equal omega-(M-/1-M) or in relaxation of coherence Gamma(MM+/-1)(not equal Gamma)-(M-/ +-M) between coherently excited M, M+/-1 magnetic sublevels. The AOC i s registered via the appearance of circular polarization (C) of fluore scence under linearly polarized excitation. The unified perturbation t reatment of a molecule in external magnetic held B is presented, accou nting for magnetic and intramolecular perturbations via interaction wi th bonded or continuum states, considering Hund's (c)-case coupling an d dividing the intramolecular perturbation operator into homogeneous ( Delta Omega=0) and heterogeneous (Delta Omega=+/-1) parts. Explicit ex pressions up to B-2 terms are given for energy shift and PD rate, adap ted to 1(u) state in conditions relevant to the B-3 Sigma(u)(-) comple x of Te-2 molecule. Numeric simulation revealed that nonlinear magneti c energy shift and heterogeneous magnetic PD produce dispersion type f luorescence circularity signals C(B) of different sign. Fitting of exp erimental data on B1(u)(-), upsilon(J)=2(96) state of Te-130(2) molecu le allowed to determine the electronic matrix element of paramagnetic Hamiltonian (Omega=0\(H) over cap(pm)\Omega=1)=G(+/-)=2.7, as well as the natural C-upsilon(het) = +/-6 s(-1/2) and the magnetic alpha(upsil on)(het) = -/+ 9 X 10(3) s-1/2 T-1 rate constants of heterogeneous PD, supposing that the B1(u)(-) state PD takes place through O-u(-) state continuum. As a result, magnetic AOC represents a sensitive method to investigate molecular structure and intramolecular interaction betwee n both bonded and continuum states. Additionally, it has been shown th at the magnetic PD effect leads to strong amplification of nonzero fie ld level crossing signals caused by B-2 terms in Zeeman energy shift. (C) 1996 American Institute of Physics.