Related Experiment Videos
Improved collisional excitation rates for interstellar water
S Green1, S Maluendes, A D McLean
1NASA Goddard Space Flight Center, Institute for Space Studies, New York 10025.
The Astrophysical Journal. Supplement Series
|March 1, 1993
Summary
Theoretical rate constants for water colliding with helium atoms were calculated. New calculations show significantly larger rate constants than previous studies, indicating convergence in theoretical models.
Area of Science:
- Chemical Physics
- Atomic and Molecular Collisions
- Quantum Chemistry
Background:
- Understanding molecular collisions is crucial for astrophysics and atmospheric science.
- Previous theoretical models for water-helium interactions had limitations.
Purpose of the Study:
- To calculate theoretical rate constants for rotational energy transfer in water-helium collisions.
- To refine understanding of water molecule dynamics in the presence of helium.
Main Methods:
- Utilized a recently improved theoretical interaction potential for water-helium.
- Calculated rate constants for para and ortho rotational levels of water.
- Covered a wide temperature range from 20 to 2000 K.
Main Results:
- Calculated rate constants are 30%-40% larger than previously reported values.
- Relative magnitudes of state-to-state rates remained largely consistent.
- The theoretical description of the water-helium system shows signs of convergence.
Conclusions:
- The improved theoretical potential yields significantly different rate constants.
- The convergence suggests a reliable theoretical framework for water-helium collisions.
- These findings contribute to more accurate modeling of interstellar and atmospheric environments.