Global potential energy surfaces for the Al+(1S) + H2 system

Area of Science:

• Quantum Chemistry
• Theoretical Chemistry
• Computational Chemistry

Background:

• Accurate potential energy surfaces (PES) are essential for understanding chemical reaction dynamics.
• The AlH2+ system presents an interesting case for studying electronic state interactions.

Purpose of the Study:

• To compute global, three-dimensional multireference ab initio potential energy surfaces for the AlH2+ system.
• To investigate the regions of surface crossings between electronic states.
• To provide analytic representations of the calculated PES for dynamics simulations.

Main Methods:

• Multireference configuration interaction (MRCI) level of theory with a large basis set.
• Calculation of potential energy surfaces for the two lowest singlet and one triplet state.
• Interpolation methodology to obtain analytic representations of the global PES.

Main Results:

• Global, 3D PES were calculated for the lowest singlet and triplet states of AlH2+.
• Two regions of surface crossings were identified: an 'early' crossing and a 'late' crossing.
• Analytic representations of the PES were obtained, and a classical simulation was performed.

Conclusions:

• The calculated potential energy surfaces and identified surface crossings are vital for modeling the dynamics of the AlH2+ system.
• The study provides a foundation for future theoretical and experimental investigations of AlH2+ reactions.