Imaging a multidimensional multichannel potential energy surface: Photodetachment of H{sup −}(NH{sub 3}) and NH{sub 4}{sup −}

• Published in: The Journal of chemical physics 2016-06, Vol.144 (24)
• Main Authors: Hu, Qichi, Johnson, Christopher J., Continetti, Robert E., Song, Hongwei, Guo, Hua, Li, Jun
• Format: Article
• Language: English
• Subjects: AMMONIA; ANGULAR DISTRIBUTION; BORN-OPPENHEIMER APPROXIMATION; ELECTRONIC STRUCTURE; GROUND STATES; INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; KINETIC ENERGY; POTENTIAL ENERGY; SURFACES
• ISSN: 0021-9606; 1089-7690

Probes of the Born-Oppenheimer potential energy surfaces governing polyatomic molecules often rely on spectroscopy for the bound regions or collision experiments in the continuum. A combined spectroscopic and half-collision approach to image nuclear dynamics in a multidimensional and multichannel system is reported here. The Rydberg radical NH{sub 4} and the double Rydberg anion NH{sub 4}{sup −} represent a polyatomic system for benchmarking electronic structure and nine-dimensional quantum dynamics calculations. Photodetachment of the H{sup −}(NH{sub 3}) ion-dipole complex and the NH{sub 4}{sup −} DRA probes different regions on the neutral NH{sub 4} PES. Photoelectron energy and angular distributions at photon energies of 1.17, 1.60, and 2.33 eV compare well with quantum dynamics. Photoelectron-photofragment coincidence experiments indicate dissociation of the nascent NH{sub 4} Rydberg radical occurs to H + NH{sub 3} with a peak kinetic energy of 0.13 eV, showing the ground state of NH{sub 4} to be unstable, decaying by tunneling-induced dissociation on a time scale beyond the present scope of multidimensional quantum dynamics.