Characterization of thymine microcrystals by CARS and SHG microscopy

Area of Science:

• Chemical Crystallography
• Spectroscopy
• Molecular Biophysics

Background:

• Identifying chemically homologous microcrystals within a polycrystal sample presents a significant analytical challenge.
• Sensitive and specific tools are required for accurate microcrystal identification and characterization.

Purpose of the Study:

• To investigate the molecular organization of thymine microcrystals using advanced spectroscopic techniques.
• To develop and apply high-resolution imaging methods for analyzing microcrystalline structures.

Main Methods:

• Utilized Second Harmonic (SHG) and Coherent Anti-Stokes Raman Scattering (CARS) spectroscopy to probe thymine molecule arrangement.
• Employed scanning microscopy in conjunction with polarization-dependent SHG and CARS intensity measurements.
• Integrated experimental findings with quantum chemistry-based theoretical interpretations.

Main Results:

• Demonstrated the capability of SHG and CARS spectroscopy to reveal the arrangement of thymine molecules in microcrystals.
• Achieved high-resolution imaging of thymine microcrystals by exploiting the polarization dependence of spectroscopic signals.
• Established a correlation between experimental observations and theoretical models.

Conclusions:

• The combined approach of advanced spectroscopy and theoretical analysis provides a powerful method for determining molecular organization in microcrystals.
• The study successfully identified the most probable molecular organization within thymine microcrystals.
• This methodology can be extended to analyze other microcrystalline systems and DNA bases.