)
contributing states. The interference observed
from the two conical intersection pathways provides a chemical analog
of Young's well-known double-slit experiment.Chemical
“double slits”: Dynamical interference of photodissociation pathways of H2O
化學
“雙狹縫”：水分子光分解途徑之量子干涉
R. N. Dixon, D. W. Huang, X. F. Yang, S. Harich, J. J. Lin, and X. Yang
Science 285, 1249 (1999)
Photodissociation of water at a wavelength of 121.6 nanometers has been
investigated by using the H-atom Rydberg tagging technique. A
striking even-odd intensity oscillation was observed in the OH(X)
product rotational distribution. Model calculations attribute this
oscillation to an unusual dynamical interference brought about by two
dissociation pathways that pass through dissimilar conical
intersections of potential energy surfaces, but result in the same
products. The interference pattern and the OH product rotational
distribution are sensitive to the positions and energies of the
conical intersections, one with the atoms collinear as H-OH and the
other as H-HO. An accurate simulation of the observations would
provide a detailed test of global H2O potential energy surfaces
for the three ()
contributing states. The interference observed
from the two conical intersection pathways provides a chemical analog
of Young's well-known double-slit experiment.
我們以氫原子雷德堡標誌(Rydberg tagging)飛行時間質譜法來研究水分子在波長121.6奈米的光分解反應動態時，發現了奇特的OH產物奇數-偶數轉動態的分佈振盪。經由理論計算發現，此反應會經過兩個角錐形位能面交叉點(conical intersection)，分別位於 H-O-H 和 H-H-O 的直線構形。H原子在位能面上的迴旋運動，導致高轉動態的OH產物，而來自於兩個交叉點的物質波，互相干涉造就了產物轉動態的奇-偶振盪。此現象和光學上的楊氏雙狹縫實驗有異曲同工之妙。
