A phthalocyanine/Ag(111) interface state is observed for the first time using time- and angle-resolved two-photon photoemission. For monolayer films of metal-free (H2Pc) and iron phthalocyanine (FePc) on Ag(111), the state exists 0.23 ± 0.03 and 0.31 ± 0.03 eV above the Fermi level, respectively. Angle-resolved spectra show the state to be highly dispersive with an effective mass of 0.50 ± 0.15 me for H2Pc and 0.67 ± 0.14 me for FePc. Density functional theory calculations on the H2Pc/Ag(111) surface allow us to characterize this state as being a hybrid state resulting from the interaction between the unoccupied molecular states of the phthalocyanine ligand and the Shockley surface state present on the bare Ag(111) surface. This work, when taken together with the extensive literature on the 3,4,9,10-perylene tetracarboxylic dianhydride/Ag interface state, provides compelling evidence that the hybridization of metal surface states with molecular electronic states is a general phenomenon.

Electron solvation is examined at the interface of a room temperature ionic liquid (RTIL) and an Ag(111) electrode. Femtosecond two-photon photoemission spectroscopy is used to inject an electron into an ultrathin film of RTIL 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ([Bmpyr](+)[NTf2](-)). While much of current literature highlights slower nanosecond solvation mechanisms in bulk ionic liquids, we observe only a femtosecond response, supporting morphology dependent and interface specific electron solvation mechanisms. The injected excess electron is found to reside in an electron affinity level residing near the metal surface. Population of this state decays back to the metal with a time constant of 400 ± 150 fs. Electron solvation is measured as a dynamic decrease in the energy with a time constant of 350 ± 150 fs. We observe two distinct temperature regimes, with a critical temperature near 250 K. The low temperature regime is characterized by a higher work function of 4.41 eV, while the high temperature regime is characterized by a lower work function of 4.19 eV. The total reorganizational energy of solvation changes above and below the critical temperature. In the high temperature regime, the electron affinity level solvates by 540 meV at 350 K, and below the critical temperature, solvation decreases to 200 meV at 130 K. This study will provide valuable insight to interface specific solvation of room temperature ionic liquids.

The picosecond photochemical dynamics of two group 8 transition metal carbonyl clusters, Fe 3 (CO) 12 and Os 3 (CO) 12 , have been studied using ultrafast time-resolved infrared spectroscopy. In both the iron and osmium clusters, no trimetallic photoproducts containing bridging carbonyls appear to be formed upon 267 or 400 nm photolysis of nonbridged parent molecules. This directly contrasts with the results of observations made previously for the Ru 3 (CO) 12 congener, in which photolysis of the nonbridged parent complex led exclusively to the formation of trimetallic photoproducts containing bridging carbonyls. In the present study, the only complex for which photolysis led to bridging carbonyl photoproducts was the bridged, C 2v isomer of Fe 3 (CO) 12 . For the iron cluster, excitation leads primarily to a mixture of transient metal−metal bond cleavage photoproducts with lifetimes on the picosecond time scale, along with Fe(CO) 4 and Fe 2 (CO) 8 photoproducts arising from fragmentation of the cluster. For the osmium cluster, similar metal−metal cleavage transients are observed to recover on the picosecond time scale, and a longer-lived carbonyl loss complex is also observed. Taken in conjunction with the existing literature on the photochemistry of the ruthenium congener, the results of this study highlight the nuanced nature of group 8 transition metal cluster photochemistry.