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Published on: May 9, 2020
Hydrated thymine cluster in the supersonic gas jet
Takeshi Kagawa1, Koji Aikawa, Fuminobu Sato
1Division of Electrical, Electronic and Information Engineering, Graduate School of Engineering, Osaka University, Suita, Osaka, Japan. kagawa@nf.eie.eng.osaka-u.ac.jp
Radiation Protection Dosimetry
|January 26, 2007
Summary
UV laser pulses at 266 nm induce fragmentation in hydrated thymine clusters. Time-of-flight mass spectrometry reveals that increasing laser intensity leads to the breakdown of thymine into smaller fragment ions.
Area of Science:
- Physical Chemistry
- Chemical Physics
- Photochemistry
Background:
- Thymine is a fundamental component of DNA.
- Understanding the behavior of hydrated thymine clusters under laser irradiation is crucial for photochemistry and radiation biology.
- Gas-phase studies provide insights into intrinsic molecular properties.
Purpose of the Study:
- To investigate the fragmentation pathways of hydrated thymine clusters induced by UV laser pulses.
- To analyze the influence of laser intensity on the fragmentation patterns.
- To identify the resulting fragment ions and understand the bond dissociation mechanisms.
Main Methods:
- Production of hydrated thymine clusters via supersonic expansion in a high vacuum.
- Irradiation of gaseous clusters with a 266 nm UV laser pulse.
- Analysis of fragment ions using time-of-flight (TOF) mass spectrometry.
- Systematic variation of laser intensity from 10^6 to 10^9 W cm^-2.
Main Results:
- At low laser intensities, hydrated thymine clusters and their larger fragments were observed.
- At intermediate intensities (10^7–10^8 W cm^-2), fragmentation of the thymine ring structure was dominant.
- Specific fragment ions like HCNH+, HNCO+, and various hydrocarbon fragments were identified, indicating C-C and C-N bond cleavage.
Conclusions:
- UV laser irradiation effectively induces fragmentation in hydrated thymine clusters.
- Laser intensity plays a critical role in determining the fragmentation pathways, from cluster dissociation to molecular bond breaking.
- The observed fragments provide evidence for the specific C-C and C-N bond scission within the thymine molecule.
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