|Title||Mechanism of Collisional Spin Relaxation in (3)Sigma Molecules|
|Publication Type||Journal Article|
|Year of Publication||2009|
|Authors||Campbell, WC, Tscherbul, TV, Lu, H-I, Tsikata, E, Krems, RV, Doyle, JM|
|Journal||PHYSICAL REVIEW LETTERS|
|Date Published||JAN 9|
We measure and theoretically determine the effect of molecular rotational splitting on Zeeman relaxation rates in collisions of cold (3)Sigma molecules with helium atoms in a magnetic field. All four stable isotopomers of the imidogen (NH) molecule are magnetically trapped and studied in collisions with He-3 and He-4. The He-4 data support the predicted 1/B-e(2) dependence of the collision-induced Zeeman relaxation rate coefficient on the molecular rotational constant B-e. The measured He-3 rate coefficients are much larger than the He-4 coefficients, depend less strongly on B-e, and theoretical analysis indicates they are strongly affected by a shape resonance. The results demonstrate the influence of molecular structure on collisional energy transfer at low temperatures.