Gas-phase Synthesis and Characterisation of the Methyl-2,2-dicyanoacetate Anion Using Photoelectron Imaging and Dipole-bound State Autodetachment.

The methyl-2,2-dicyanoacetate anion is synthesised in an electrospray ionisation source through a gas-phase reaction involving tetracyanoethylene and methanol. Photoelectron imaging is used to determine the isomeric form of the product. The photoelectron spectra and angular distributions are only consistent with a single isomer. Additionally, mode-specific vibrational autodetachment is observed. This can be correlated with the emission from a photoexcited dipole-bound state by considering the IR spectrum of the neutral molecule, adding further confirmation of the isomeric form and providing a binding energy of the dipole-bound state. Our experiments show how conventional photoelectron imaging can be used to determine detailed information about gas-phase reaction products.