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Molecular structure-property correlations from optical nonlinearity and thermal-relaxation dynamics
Indrajit Bhattacharyya1, Shekhar Priyadarshi, Debabrata Goswami
1Department of Chemistry, Indian Institute of Technology, Kanpur 208 016, India.
Chemical Physics Letters
|July 14, 2009
Summary
We measured nonlinear optical properties of alcohols using ultrafast Z-scan. Thermal effects were removed to reveal structure-property relationships, showing thermal diffusivity decreases with alcohol chain length.
Area of Science:
- Nonlinear optics
- Molecular spectroscopy
- Materials science
Background:
- Primary alcohols exhibit nonlinear optical effects.
- Understanding these effects is crucial for optical applications.
- Thermal properties influence nonlinear optical responses.
Purpose of the Study:
- To measure nonlinear absorption and refraction coefficients of primary alcohols at 1560 nm.
- To investigate the influence of thermal effects on nonlinear optical measurements.
- To determine the relationship between molecular structure and thermal properties.
Main Methods:
- Ultrafast single beam Z-scan technique.
- Frequency-optimized optical chopper to eliminate thermal effects.
- Thermal lens pump-probe experiments at 1560 nm and 780 nm.
Main Results:
- Saturation absorption and nonlinear refraction coefficients were measured.
- Distinct faster (conduction) and slower (convection) thermal relaxation timescales were identified.
- Thermal diffusivity was accurately predicted from the faster timescale.
- Thermal diffusivity showed a linear decrease with increasing alcohol chain length.
Conclusions:
- Nonlinear optical properties are influenced by vibronic transitions and cubic nonlinearity.
- Thermal effects significantly impact nonlinear optical measurements in alcohols.
- A clear structure-property relationship exists, with thermal diffusivity inversely related to molecular size.
- This study confirms the link between molecular structure and thermal-diffusivity in alcohols.
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