Directions of transition dipole moments of t-butyl nitrite obtained via orientation with a strong, uniform electric field

Abstract

A strong, uniform electric field was used to orient supersonically cooled t-butyl nitrite for measurements of directions of transition dipole moments. The oriented sample was dissociated with linearly polarized light, and the NO fragments were studied by (1+1) REMPI through the A 2Σ+ state. At photolysis wavelengths of 365.8 and 351.8 nm, there was a 47% enhancement in the NO signal when the photolysis beam was polarized perpendicular to the orientation field, implying a perpendicular relationship between the transition dipole of the S1 state and the permanent dipole. Photodissociation at 250 and 224 nm showed the opposite trend, with a 46% enhancement in the NO signal when the photolysis beam was polarized parallel to the orientation field. The transition dipole of the S2 state was therefore determined to be parallel to the permanent dipole. This experiment demonstrates the application of brute force orientation for obtaining directions of transition dipole moments.