Physical Sciences and Mathematics Commons^™

Bh2 Revisited: New, Extensive Measurements Of Laser-Induced Fluorescence Transitions And Ab Initio Calculations Of Near-Spectroscopic Accuracy, Fumie X. Sunahori, Mohammed Gharaibeh, Dennis J. Clouthier, Riccardo Tarroni

Chemistry Faculty Publications

The spectroscopy of gas phase BH₂ has not been explored experimentally since the pioneering study of Herzberg and Johns in 1967. In the present work, laser-induced fluorescence (LIF) spectra of the òB₁(Πu)-X̃²A₁ band system of ¹¹BH₂, ¹⁰BH₂, ¹¹BD₂, and ¹⁰BD₂ have been observed for the first time. The free radicals were "synthesized" by an electric discharge through a precursor mixture of 0.5% diborane (B₂H₆ or B₂D₆) in high pressure argon at the exit of …

Collectivity Of 0+ States In 160Gd, S. R. Lesher, C. Casarella, A. Aprahamian, B. P. Crider, R. Ikeyama, I. R. Marsh, Marcus T. Mcellistrem, Erin E. Peters, F. M. Prados-Estévez, M. K. Smith, Z. R. Tully, J. R. Vanhoy, Steven W. Yates

Chemistry Faculty Publications

Excited 0⁺ states in ¹⁶⁰Gd have been examined with the (n,n′γ) reaction at incident neutron energies up to 2.8 MeV. Gamma-ray excitation functions and angular distribution measurements allow the confirmation of the existence of 0⁺ states at 1379.70 keV and 1558.30 keV, but we reject the assignments of additional previously suggested 0⁺ candidates. Limits on the level lifetimes of the observed 0⁺ states permit an evaluation of the collectivity of these states.

The Requisite Electronic Structure Theory To Describe Photoexcited Nonadiabatic Dynamics: Nonadiabatic Derivative Couplings And Diabatic Electronic Couplings, Joseph E. Subotnik, Ethan Alguire, Qi Ou, Brian R. Landry, Shervin Fatehi

Chemistry Faculty Publications and Presentations

Conspectus

Electronically photoexcited dynamics are complicated because there are so many different relaxation pathways: fluorescence, phosphorescence, radiationless decay, electon transfer, etc. In practice, to model photoexcited systems is a very difficult enterprise, requiring accurate and very efficient tools in both electronic structure theory and nonadiabatic chemical dynamics. Moreover, these theoretical tools are not traditional tools. On the one hand, the electronic structure tools involve couplings between electonic states (rather than typical single state energies and gradients). On the other hand, the dynamics tools involve propagating nuclei on multiple potential energy surfaces (rather than the usual ground state dynamics).

In this …

Applied Quantum Chemistry: Spectroscopic Detection And Characterization Of The F2Bs And Cl2Bs Free Radicals In The Gas Phase, Bing Jin, Phillip M. Sheridan, Dennis J. Clouthier

Chemistry Faculty Publications

In this and previous work [D. J. Clouthier, J. Chem. Phys. 141, 244309 (2014)], the spectroscopic signatures of the X₂BY (X = H, halogen, Y = O, S) free radicals have been predicted using high level ab initio theory. The theoretical results have been used to calculate the electronic absorption and single vibronic level (SVL) emission spectra of the radicals under typical jet-cooled conditions. Using these diagnostic predictions, the previously unknown F₂BS and Cl₂BS free radicals have been identified and characterized. The radicals were prepared in a free jet expansion by subjecting precursor …

An Experimental And Theoretical Study Of The Electronic Spectrum Of The Hbcl Free Radical, Mohammed A. Gharaibeh, Ramya Nagarajan, Dennis J. Clouthier, Riccardo Tarroni

Chemistry Faculty Publications

Following our previous discovery of the spectra of the HBX (X = F, Cl, and Br) free radicals [S.-G. He, F. X. Sunahori, and D. J. Clouthier, J. Am. Chem. Soc. 127, 10814 (2005)], the òA″Π-X̃²A' band systems of the HBCl and DBCl free radicals have been studied in detail. The radicals have been prepared in a pulsed electric discharge jet using a precursor mixture of BCl₃ and H₂ or D₂ in high pressure argon. Laser-induced fluorescence (LIF) and single vibronic level emission spectra have been recorded to map out the ground …