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Physical Sciences and Mathematics Commons™
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Full-Text Articles in Physical Sciences and Mathematics
Origins Of The Quantum Efficiency Duality In The Primary Photochemical Event Of Bacteriorhodopsin, Robert R. Birge, Leonore A. Findsen, Albert F. Lawrence, Mark Masthay, Chian-Fan Zhang
Origins Of The Quantum Efficiency Duality In The Primary Photochemical Event Of Bacteriorhodopsin, Robert R. Birge, Leonore A. Findsen, Albert F. Lawrence, Mark Masthay, Chian-Fan Zhang
Chemistry Faculty Publications
Experimental and theoretical evidence is presented which suggests that two distinct forms of light-adapted bacteriorhodopsin may exist. We propose that these two forms have characteristic photocycles with significantly different primary quantum yields. INDO-PSDCI molecular orbital procedures and semiempirical molecular dynamics simulations predict that one ground state geometry of bR undergoes photochemistry with a primary quantum yield, Φ1, of ~ 0.27, and that a second ground state geometry, with a slightly displaced counterion, yields Φ1 ~ 0.74. This theoretical model is supported by the observation that literature measurements of Φ1 tend to fall into one of two categories- those that observe …
The Spectroscopy And A State Dynamics Of The Neibr Van Der Waals Complex, William Robert Simpson , '88, Thomas Alex Stephenson
The Spectroscopy And A State Dynamics Of The Neibr Van Der Waals Complex, William Robert Simpson , '88, Thomas Alex Stephenson
Chemistry & Biochemistry Faculty Works
The A 3Π1←X 1Σ+ laser‐induced fluorescence excitation spectrum of the NeIBr van der Waals complex is reported and analyzed to extract information regarding the structure and vibrational predissociation dynamics of the complex. While no definitive geometric information regarding NeIBr is obtained, our data indicate that a linear geometry is at least plausible. The vibrational predissociation lifetimes are a strong function of A state vibrational level and range from 2.6 to 23 ps. The variation in lifetime with vibrational level is consistent with the results of previous measurements on rare gas–halogen complexes, particularly NeBr2.
The Exchange Potential In Path Integral Studies: Analytical Justification, Randall W. Hall
The Exchange Potential In Path Integral Studies: Analytical Justification, Randall W. Hall
Collected Faculty and Staff Scholarship
We present analytical justification for our previously described exchange pseudopotential. We show how the fermi quantum partition function can be constructed from the Boltzmann (distinguishable particle) wave functions if the states that correspond to like‐spin electrons occupying the same quantum state are excluded. A class of weighting functions that satisfy this constraint approximately is discussed. Our previous pseudopotential falls under this class. Essentially, our pseudopotential forces the unwanted states to have high energy and, hence, to make negligible contribution to the partition function. Exchange potentials of the form discussed in this article should be useful for studying systems where the …
Friedrich Wöhler, John Alfred Heitmann
Friedrich Wöhler, John Alfred Heitmann
History Faculty Publications
Friedrich Wöhler synthesized urea in 1828 and thus first demonstrated that organic materials, heretofore believed to possess a vital force, need not be made exclusively within living organisms. He also isolated aluminum metal in 1827 and discovered the elements beryllium and yttrium.