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Direct Imaging of Laser-driven Ultrafast Molecular Rotation
Published on: February 4, 2017
Kramers-Kronig transformation for optical rotatory dispersion studies
1Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235, USA. Prasad.L.Polavarapu@vanderbilt.edu
The Journal of Physical Chemistry. A
|July 13, 2006
Summary
The Kramers-Kronig transform accurately converts electronic circular dichroism (ECD) to optical rotatory dispersion (ORD) for simple molecules. This method offers a computationally efficient alternative for predicting ORD, especially in the resonant region.
Area of Science:
- Computational Chemistry
- Spectroscopy
Background:
- Optical rotatory dispersion (ORD) and electronic circular dichroism (ECD) are crucial spectroscopic techniques.
- The Kramers-Kronig (KK) transform is a theoretical tool linking ORD and ECD.
- Accurate numerical methods are essential for applying the KK transform.
Purpose of the Study:
- To analyze the Kramers-Kronig (KK) transform method for deriving optical rotatory dispersion (ORD) from electronic circular dichroism (ECD).
- To evaluate different numerical integration techniques for the KK transform.
- To compare KK-derived ORD with results from the linear response method.
Main Methods:
- Evaluation of three numerical integration methods for the KK transform.
- Application of the Ohta and Ishida numerical method.
- Quantum mechanical calculations of ECD and conversion to ORD via KK transform.
- Comparison with ORD derived from the linear response method.
Main Results:
- The KK transform of ECD accurately predicts ORD for molecules with monosignate ORD in the nonresonant region.
- The KK method may yield inaccurate results for molecules with bisignate ORD.
- The KK transform serves as a computationally economical method for predicting ORD in the resonant region.
- The KK transform allows direct conversion of experimental ECD spectra without curve fitting.
Conclusions:
- The KK transform is a viable and computationally efficient method for deriving ORD from ECD, particularly in the resonant region.
- The accuracy of the KK transform method depends on the spectral characteristics (monosignate vs. bisignate ORD).
- The KK transform offers practical advantages over sum-over-states methods for ORD prediction from experimental ECD data.
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