Photodissociation of : A Non-Adiabatic Dynamics Investigation

Area of Science:

• Photochemistry
• Computational Chemistry
• Coordination Chemistry

Background:

• Metal carbonyl complexes with α-diimine ligands show emission and ligand-selective photodissociation from MLCT states.
• Experimental study of ultrafast photodissociation mechanisms is challenging due to femtosecond timescales and spectral overlap.

Purpose of the Study:

• Investigate the photodissociative mechanism of a prototypical metal carbonyl complex using non-adiabatic dynamic simulations.
• Characterize the excited-state dynamics and photodissociation pathway.

Main Methods:

• Non-adiabatic dynamic simulations were employed.
• The photochemistry of a specific metal carbonyl complex was modeled.

Main Results:

• An 86 fs lifetime for the bright excited state and a 13% quantum yield were obtained, aligning with experimental data.
• Simulations suggest a ballistic photodissociation mechanism, independent of the electronic state.
• This contrasts with previously proposed mechanisms involving intersystem crossing and dissociation.

Conclusions:

• The ballistic photodissociation mechanism is proposed for this class of compounds.
• Axial photodissociation selectivity arises from the absence of an avoided crossing in the equatorial direction.