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## Full-Text Articles in Physics

An Experimental And Theoretical Study Of *Ã*^{2}*A"*Π–*X*^{~2}*A'* Band System Of The Jet-Cooled Hbbr/Dbbr Free Radical, Mohammed Gharaibeh, Dennis J. Clouthier, Riccardo Tarroni

#### An Experimental And Theoretical Study Of Ã2A"Π–X~2A' Band System Of The Jet-Cooled Hbbr/Dbbr Free Radical, Mohammed Gharaibeh, Dennis J. Clouthier, Riccardo Tarroni

*Chemistry Faculty Publications*

The electronic spectra of the HBBr and DBBr free radicals have been studied in depth. These species were prepared in a pulsed electric discharge jet using a precursor mixture of BBr_{3} vapor and H_{2} or D_{2} in high pressure argon. Transitions to the electronic excited state of the jet-cooled radicals were probed with laser-induced fluorescence and the ground state energy levels were measured from the single vibronic level emission spectra. HBBr has an extensive band system in the red which involves a linear-bent transition between the two Renner-Teller components of what would be a ^{2}Π state ...

Hyperfine Rather Than Spin Splittings Dominate The Fine Structure Of The *B* ^{4}Σ^{-}–*X* ^{4}Σ^{-} Bands Of Aic, Dennis J. Clouthier, Aimable Kalume

#### Hyperfine Rather Than Spin Splittings Dominate The Fine Structure Of The B 4Σ-–X 4Σ- Bands Of Aic, Dennis J. Clouthier, Aimable Kalume

*Chemistry Faculty Publications*

Laser-induced fluorescence and wavelength resolved emission spectra of the *B *^{4}Σ^{−}–*X* ^{4}Σ^{−} band system of the gas phase cold aluminum carbide free radical have been obtained using the pulsed discharge jet technique. The radical was produced by electron bombardment of a precursor mixture of trimethylaluminum in high pressure argon. High resolution spectra show that each rotational line of the 0-0 and 1-1 bands of AlC is split into at least three components, with very similar splittings and intensities in both the *P*- and *R*-branches. The observed structure was reproduced by assuming *b*_{βS} magnetic hyperfine coupling ...

Double Excitations Within Time-Dependent Density Functional Theory Linear Response, Neepa T. Maitra, Fan Zhang, Robert J. Cave, Kieron Burke

#### Double Excitations Within Time-Dependent Density Functional Theory Linear Response, Neepa T. Maitra, Fan Zhang, Robert J. Cave, Kieron Burke

*All HMC Faculty Publications and Research*

Within the adiabatic approximation, time-dependent density functional theory yields only single excitations. Near states of double excitation character, the exact exchange–correlation kernel has a strong dependence on frequency. We derive the exact frequency-dependent kernel when a double excitation mixes with a single excitation, well separated from the other excitations, in the limit that the electron–electron interaction is weak. Building on this, we construct a nonempirical approximation for the general case, and illustrate our results on a simple model.

Calculation Of Electronic Coupling Matrix Elements For Ground And Excited State Electron Transfer Reactions: Comparison Of The Generalized Mulliken–Hush And Block Diagonalization Methods, Robert J. Cave, Marshall D. Newton

#### Calculation Of Electronic Coupling Matrix Elements For Ground And Excited State Electron Transfer Reactions: Comparison Of The Generalized Mulliken–Hush And Block Diagonalization Methods, Robert J. Cave, Marshall D. Newton

*All HMC Faculty Publications and Research*

Two independent methods are presented for the nonperturbative calculation of the electronic coupling matrix element (Hab) for electron transfer reactions using ab initio electronic structure theory. The first is based on the generalized Mulliken–Hush (GMH) model, a multistate generalization of the Mulliken Hush formalism for the electronic coupling. The second is based on the block diagonalization (BD) approach of Cederbaum, Domcke, and co-workers. Detailed quantitative comparisons of the two methods are carried out based on results for (a) several states of the system Zn2OH2+ and (b) the low-lying states of the benzene–Cl atom complex and its contact ion ...

A Theoretical Investigation Of The Ground And Low‐Lying Excited States Of Butadiene Radical Cation, Robert J. Cave, Michael G. Perrott '90

#### A Theoretical Investigation Of The Ground And Low‐Lying Excited States Of Butadiene Radical Cation, Robert J. Cave, Michael G. Perrott '90

*All HMC Faculty Publications and Research*

Results are presented from ab initio calculations on the ground and several low‐lying excited states of the butadiene radical cation. In particular, we have calculated geometries for the ground and several excited states at the multiconfiguration self‐consistent field level and characterized the planar stationary points. The vertical ionization potentials from the neutral molecule ground state and vertical excitation energies at the computed equilibrium geometry of the cation were also examined. A variety of methods were tested for the calculation of ionization potentials and excitation energies, including multiconfiguration self‐consistent field, multireference singles and doubles configuration interaction (with and ...

Preliminary Rovibrational Analysis Of The Nν6+Ν1−Nν6 Vibration In Hcn⋅⋅⋅Hf, E. Kyrö, K. Mcmillan, M. Eliades, D. Danzeiser, P. Shoja-Chaghervand, Shannon Lieb, J. W. Bevan

#### Preliminary Rovibrational Analysis Of The Nν6+Ν1−Nν6 Vibration In Hcn⋅⋅⋅Hf, E. Kyrö, K. Mcmillan, M. Eliades, D. Danzeiser, P. Shoja-Chaghervand, Shannon Lieb, J. W. Bevan

*Scholarship and Professional Work - LAS*

A preliminary rotation‐vibration analysis of the *n*=0 and *n*=1 subbands associated with the *n*ν_{6}+ν_{1}−*n*ν_{6} hydrogen‐bonded vibration in HCN⋅⋅⋅HF has been completed. The following excited staterotational constants*B*′ and band origin frequencies ν_{0} have been determined for the complex. The results are consistent with a rotation‐vibration interaction constant α_{1}=−68.3±1 MHz which correlates with an excited state*r*(*N*⋅⋅⋅*F*) internuclear distance of 2.762 Å, a decrease of 0.034 Å relative to the ground state.Excited state lifetimes associated with assigned transitions ...