Molecules on Metals : Shaping Energy Landscapes and Dynamics

Metal surfaces provide unique reaction fields where molecules can exhibit behaviors unattainable in isolation. To elucidate such behaviors, we have proposed a localized theoretical framework that treats adsorbed molecules as open quantum subsystems. Within this framework, we have constructed an effective Hamiltonian incorporating resonance lifetimes via complex energy eigenvalues, which is realized through our open-boundary cluster model (OCM). This model captures surface photodynamics by eliminating artificial level repulsions present in isolated conventional cluster models. We demonstrate that OCM-derived excited-state potential energy surfaces naturally describe ultrafast electron transfer and wavepacket dynamics following photoexcitation. Furthermore, we investigate plasmon–molecule strong coupling on metal nanoparticles, showing that even in the absence of light, localized surface plasmons can reshape molecular potential energy surfaces and reduce the photon energy required for photodissociation. Through these studies, we aim to illuminate the complex and surprising behavior of molecules at metal interfaces.