DIRECT SPECTROSCOPIC DETERMINATION OF THE DEGREE OF ORIENTATION OF PARITY-SELECTED NO

If a polar molecule can be selected in a rotational state of definite parity, subsequent orientation of the molecule in an electric field mi xes opposite parity states. The degree of mixing reflects the degree o f orientation. Therefore, the intensity ratio of spectral lines that c orrespond to transitions starting from the two parity states being mix ed, forms a sensitive and accurate probe of the molecular orientation. If saturation of the spectral lines of interest is avoided, the absol ute degree of orientation can be determined, without recourse to other experimental data but line intensities. The method is illustrated for the case of the NO molecule. (C) 1998 Published by Elsevier Science B .V. All rights reserved.