ONGOING AND RECENT RESEARCH WORK (1996-2014)


         Optical properties of nanostructured semiconductor surfaces and of silicon quantum dots (D. S. Kilin, A. S. Leathers, J. Ramirez, C. Obara, D. Arlund, T. LaJoie, T. Vazhappilly, R. Hembree, M. Mavros, D. Stewart, R. Pulido, H. Freitag, J. Boulos, N. Vinson, and D. A. M.)


 

 

TOC1-tif

 

 

Above: Isocontours of photoinduced electron and hole populations vs energy level (V) and vs log(t) (H) (left) for a Ag cluster adsorbed on a Si slab as they relax after excitation. Real and imaginary parts of the dielectric function for a Si slab photoexcited by light (right)

 

 

 

 

 

 


 

 

 

 

Above: Si29H36and Si35H36 quantum dots with P and Al dopants inside and outside, and oriented; rates of energy transfer have been calculated from TDDFT and the Foerter equation for electronic energy transfer.

 


 

 

Above: Amorphous Si (left) and photovoltage (right) compared with experiment (red dots)

Above: Ag3Si:H slab (left), indirect electron transfer (middle) and charge transfer over time (right)

         Dissipative dynamics of molecular systems and materials using the density matrix (Z. Yi, A. Santana, B. Thorndyke, A. Leathers, D. Kilin, R. Hembree, and D. A. M.)

zindoyield

 

         Electronic rearrangement and light emission in collisions of atomic ions with atoms, using time-dependent molecular orbitals and time-dependent Hartree-Fock theory.(K. Runge, H. DaCosta and D. A. M.; B. Thorndyke; A. Reyes; A. Pacheco)

lightemissiont450-700

p-sigma-final

         Electron transfer in the scattering of alkali ions by metal surfaces of W, Ni and Cu. Calculation of cross sections for neutralization and for orbital polarization. ( C. DeMelo, B. Kirtman, and D. A. M.; A. Pacheco; A. Leathers)

         Energy transfer in the scattering of atoms by surfaces and diatomic adsorbates, leading to vibrational excitation of adsorbates. Applications to scattering of Li and He beams from W surfaces and from CO adsorbed on Ni and Cu .(S. Miret-Artes, J. L. Vega, J. P. Toennies, and D. A. M.; Z. Parra and D.A.M.)

         Photodesorption by visible and UV radiation of diatomic molecules adsorbed on surfaces, such as CO on Ni and Cu metals. Calculation of line shapes in steady-state experiments, and of lifetimes in pulsed light experiments.(D. Beksic; S. Miret-Artes; J. Sund; Z. Yi; A. Salam; A. Santana-Vargas; and D. A. M.; S. Villaume; N. Finck)

         Molecular rearrangement involving electronic transition in collisions of hydrogen, alkali and alkali-earth atoms with atoms and diatomics, in terms of self-consistent eikonal methods, and algebraic methods.( G. Delgado-Barrio, M. Fernandez, and D. A. M.)

         Molecular photodissociation by visible and UV radiation, particularly of C-I bonds in polyatomic molecules. Calculation of line shapes.(C. Stodden and D. A. M.)

         Energy transfer in collisions of hyperthermal hydrogen, helium and alkali atoms with molecules and surfaces, using a general collisional time-correlation function approach including dissipation. Calculation of cross sections measured in time-of-flight experiments, and of final distributions of product states in gases.(H. Kim; D. Rojas; S. Miret-Artes, J. L. Vega; and D. A. M.)

         Isomerization dynamics of atomic clusters of transition metal ions in rare gas atoms (R. Asher, P. Brucat, and D. A. M.)

         Electronic spectra of atoms excited in atomic and molecular clusters.(G. Diercksen and D. A. M.; B. Thorndyke; A. Leathers)

         Visualization and animation of collisional electron transfer, and of photodesorption.(K. Runge; S. Wallace; J. Sund; Z. Yi; D. A. M.; B. Thorndyke; A. Pacheco)