Ab initio Calculated Rotation-Vibration Linestrengths for HeH2+

Area of Science:

• Theoretical Chemistry
• Quantum Mechanics
• Molecular Spectroscopy

Background:

• The helium hydride ion (HeH2+) is a simple triatomic molecule with astrophysical relevance.
• Previous studies determined its potential energy surface, but its spectral properties remained largely uncharacterized.

Purpose of the Study:

• To calculate the electric dipole moment components of HeH2+.
• To determine the bound rotation-vibration energy levels and transition line strengths.
• To assess the feasibility of observing the HeH2+ rotation-vibration spectrum.

Main Methods:

• Utilizing variational configuration interaction wavefunctions to compute electric dipole moment components.
• Employing the Sutcliffe-Tennyson Hamiltonian to evaluate energy levels and line strengths.
• Fitting potential energy and dipole moment functions from calculated data.

Main Results:

• Electric dipole moment components were calculated using variational methods.
• Bound rotation-vibration energy levels and transition line strengths were determined.
• Strong infrared transitions were predicted in the 500-800 cm-1 range, particularly for stretching motions.

Conclusions:

• The calculated spectral properties suggest favorable conditions for detecting the HeH2+ rotation-vibration spectrum.
• This work provides crucial data for guiding experimental efforts in observing this molecular ion.
• The findings contribute to a deeper understanding of HeH2+ molecular physics.