Quantum-state resolved reaction dynamics at the gas-liquid interface: Direct absorption detection of HF(v,J) product from F(P2)+Squalane

Abstract

Exothermic reactive scattering of F atoms at the gas-liquid interface of a liquid hydrocarbon (squalane) surface has been studied under single collision conditions by shot noise limited high-resolution infrared absorption on the nascent HF ( v , J ) product. The nascent HF ( v , J ) vibrational distributions are inverted, indicating insufficient time for complete vibrational energy transfer into the surfaceliquid. The HF ( v = 2 , J ) rotational distributions are well fit with a two temperature Boltzmann analysis, with a near room temperature component ( T TD ≈ 290 K ) and a second much hotter scattering component ( T HDS ≈ 1040 K ) . These data provide quantum state level support for microscopic branching in the atom abstraction dynamics corresponding to escape of nascent HF from the liquid surface on time scales both slow and fast with respect to rotational relaxation.