Photofragment helicity caused by matter-wave interference from multiple dissociative states

Science

Volumn 281, Issue 5381, 1998, Pages 1346-1349

  Rakitzis, T Peter ^a   Kandel, S Alex ^a   Alexander, Andrew J ^a   Kim, Zee Hwan ^a   Zare, Richard N ^a  

^a NONE

Author keywords

[No Author keywords available]

Indexed keywords

IODINE;

ARTICLE; ENERGY TRANSFER; MOLECULAR DYNAMICS; PRIORITY JOURNAL; QUANTUM MECHANICS; SPECTRAL SENSITIVITY;

EID: 0032575684     PISSN: 00368075     EISSN: None     Source Type: Journal    
DOI: 10.1126/science.281.5381.1346     Document Type: Article

References (26)

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6. In the celebrated Young's two-slit experiment, the interference of light passing through two slits causes a bright and dark fringe pattern to appear on a screen, the intensity of which varies as cosΔφ (where Δφ is the phase difference between the two paths). If instead, the light used is initially linearly polarized, and crossed polarizers are placed in front of the two slits (at 45° to the linear polarization so that both slits transmit equally), then the light on the screen no longer shows an intensity fringe pattern, but shows instead a polarization fringe pattern. This polarization pattern can be separated into components with linearly polarized variations (proportional to cosΔφ) and circularly polarized variations (proportional to sinΔφ). The analog of this special two-slit experiment in molecular photolysis is that in which the interference of matter waves from potential surfaces of different symmetry causes angular momentum polarization of the photofragments [for discussions and examples of cosΔφ variations in the alignment of photofragments, see E. Flemming, O. Wilhelmi, H. Schmoranzer, M. Glass-Maujean, J. Chem. Phys. 103, 4090 (1995) and (4, 5, 25)]. The experiment described in the present report is an example of the sinΔφ variations in photofragment helicity.
7. We thank S. Yabushita for permission to use his ab initio calculations of the excited states of ICl.
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11. In such crystals, the wavelength and speed of light that is linearly polarized parallel to the optical axis of the crystal differs from that which is linearly polarized perpendicular to the optical axis. Light that is polarized at some angle (such as 45°) to the optical axis has components that are parallel and perpendicular to the optical axis. These components, which were in phase upon entering the crystal, change phase as the light propagates through the crystal. A phase difference of a quarter wave upon exiting the crystal produces pure circularly polarized light.
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23. For the photolysis of polyatomic systems, photofragment helicity should be detectable under the following conditions: one photofragment is detected in a state-specific manner, and its velocity distribution is detected with an energy resolution greater than the internal energy spacings of the undetected fragment. For poorer energy resolution, some reduction in the photofragment helicity is expected but may not be severe, depending on how rapidly the photofragment helicity varies with the internal state of the undetected photofragment.
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26. Support from the NSF under grant number CHE-93-22690 is gratefully acknowledged.