Modified Gaussian Wave Packet Method for Calculating Initial State Wave Functions in Photodissociation

Area of Science:

• Quantum chemistry
• Computational physics
• Molecular dynamics

Background:

• Calculating ground state wave functions is crucial for understanding molecular properties.
• Existing methods may face challenges with accuracy and computational cost for complex systems.

Purpose of the Study:

• To introduce a modified Gaussian wave packet relaxation method for accurate ground state wave function calculation.
• To validate the method's performance in molecular photodissociation dynamics.

Main Methods:

• Utilizing an expansion of frozen Gaussian wave packets.
• Employing a two-step relaxation process involving imaginary time propagation and coefficient optimization.
• Applying the method to the photodissociation of nitroxyl chloride (NOCl) and ammonia (NH3).

Main Results:

• The method accurately reproduces molecular energies, wave functions, and absorption spectra.
• Achieved excellent agreement with exact results for both NOCl and NH3 photodissociation.
• Successfully reproduced the highly structured absorption spectrum of NH3.

Conclusions:

• The modified Gaussian wave packet relaxation method is a reliable and accurate approach for quantum dynamics simulations.
• The technique demonstrates high fidelity in capturing both initial wave packet behavior and excited state propagation.
• This method offers a promising computational tool for studying molecular photodissociation and related phenomena.