W. Carl LINEBERGER
Professor Lineberger is interested in the structure and stability of ions and free radicals, photoelectron spectroscopy of anions, and photophysics and dynamics of cluster ions. The experimental methods all involve the interaction of laser radiation with mass-selected ion beams. Though they all work in concert, the experiments used by Professor Lineberger can be divided in three groups:
First, the absorption of light by a negative ion produces an electron-neutral complex in a total energy state defined by the photon energy. The Lineberger group utilizes this concept in a tunable laser photodetachment machine to probe electron-neutral interactions with unprecedented resolution (10-8 eV). This technique allows the researchers to probe vibration and rotation to electronic coupling, for example, in the autodetachment of PtN. The rotational and vibrational mode dependence of autodetachment rates of dipole bound excited states of C3H2- is another area of current interest.
A second method to probe negative ion structure is via photoelectron spectroscopy of negative ions. This approach also provides direct information on the structure and internal energy of the neutral species produced in the photodetachment process. The group can study species that have only a fleeting existence, such as vinylidene, H2CC. Systems of current interest include diradicals, a variety of carbenes, and transition metal clusters. Future projects include studies of adsorbates on transition metal clusters.
Another area of interest is the photophysics of both positive and negative cluster ions. Photofragmentation of clusters, e.g., (CO2)n+, (CO2)n, I2-(CO2)n and Arn+, has been studied recently. The time-resolved photodissociation and recombination of clusters such as I2-(CO2)n, I2-(N2O)n and I2-(OCS)n are being pursued using femtosecond lasers.
W.C. Lineberger, K.M. Ervin, I. Anusiewicz, P. Skurski and J. Simons, "The only stable state of O2- is the X2IIg ground state and it (still!) has an adiabatic electron detachment energy of 0.45 eV", submitted to J. Chem. Phys., (2003).
W.C. Lineberger and A. Sanov, "Dynamics of cluster anions: a detailed look at condensed-phase interactions", PhysChemComm, 5(25), 165-177, (2002).
W.C. Lineberger, M.R. Nimlos, G. Davico, C.M. Geise, P.G. Wenthold, S.J. Blanksby, C.M. Hadad, G.A. Petersson and G.B. Ellison, "Photoelectron spectroscopy of HCCN-and HCNC- reveals the quasilinear triplet carbenes, HCCN and HCNC", J. Chem. Phys., 117, 4323-4339, (2002).
Carl Lineberger, Adam Gianola and Django Andrews, "On the Photoelectron Spectrum of AgO", J. Chem. Phys. 117, 4074-6 (2002).
W.C. Lineberger, X. Duan, L. W. Burggraf, D. E. Weeks, G. E. Davico, and R. L. Schwartz, "Photoelectron spectroscopy of Si2C3- and quantum chemistry of the linear Si2C3 cluster and its isomers", J. Chem. Phys., 116(9), 3601-11 (2002).
W.C. Lineberger, T. M. Ramond, S. J. Blanksby, S. Kato, V. M. Bierbaum, G. E. Davico, R. L. Schwartz, and G. B. Ellison, "The Heat of Formation of the Hydroperoxyl Radical HOO via negative Ions", J. Phys. Chem., 106, 9641-47 (2002).
W.C. Lineberger, T. M. Ramond, G. E. Davico, F. Hellberg, F. Svedberg, P. Salén, and P. Söderqvist, "Photoelectron Spectroscopy of Nickel, Palladium, and Platinum Oxide Anions,"J. Mol. Spectrosc., 216, 1-14, (2002).
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