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Search Publications by: David F. Plusquellic (Fed)

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Displaying 26 - 50 of 115

Rotationally Resolved C2 Symmetric Conformers of Bis-(4-hydroxyphenyl)methane: Textbook Examples of Excitonic Coupling in the S1 and S2 Electronic States

September 1, 2011
Author(s)
Shin G. Chou, Chirantha P. Rodrigo, Christian Muller, Kevin O. Douglass, Timothy Zwier, David F. Plusquellic
Rotationally resolved microwave and ultraviolet spectra of jet-cooled bis-4 hydroxy)-diphenylmethane (b4HBM) have been obtained using Fourier-transform microwave and UV laser/molecular beam spectrometers. A recent vibronic level study of b4HPM1 has

State Resolved THz Spectroscopy and Dynamics of Crystalline Peptide/Water Systems

July 11, 2011
Author(s)
Zeeshan Ahmed, Shin G. Chou, Karen M. Siegrist, David F. Plusquellic
State resolved THz studies of crystalline peptides and their hydrates have provided precise measures of the infrared active phonon modes that reflect motions on the longest possible length scales in these systems. The impact of co-crystallized water on the

Conformer-specific vibronic spectroscopy and vibronic coupling in a flexible bichromophore: bis-(4-hydroxyphenyl)methane

April 28, 2011
Author(s)
Chirantha P. Rodrigo, Christian Muller, Nathan Pillsbury, William H. James III, David F. Plusquellic, Timothy Zwier
The vibronic spectroscopy of jet-cooled bis-(4-hydroxyphenyl)methane (b4HPM) has been explored using fluorescence excitation (FE), dispersed fluorescence (DFL), UV-UV holeburning (UVHB), UV depletion (UVD), and fluorescence-dip infrared (FDIR)

Chirped-pulse terahertz spectroscopy for broadband trace gas sensing

April 22, 2011
Author(s)
Eyal Gerecht, Kevin O. Douglass, David F. Plusquellic
We report the first demonstration of a broadband trace gas sensor based on chirp-pulse terahertz spectroscopy. The advent of newly developed solid state sources and heterodyne detectors for the terahertz frequency range have made it possible to generate

Organic Compounds in the C3H6O3 Family: Microwave Spectrum of cis-cis-Dimethyl Carbonate

October 18, 2010
Author(s)
Francis J. Lovas, David F. Plusquellic, Susanna L. Widicus Weaver, B. A. McGuire, G. A. Blake
Geometry optimization calculations on 13 members of the C3H6O3 family of organic species have been carried out to determine their relative binding energies. Dimethyl carbonate [(CH3)2CO3] is one of the lower energy species in this family, which includes

International Comparability in Circular Dichroism: II

October 4, 2010
Author(s)
Curtis W. Meuse, Jascindra Ravi, Paulina Rakowska, Tommaso Garfagnini, Alex E. Knight, Philippe Charlet, Julie D. Lorenz, Christopher Jones, David F. Plusquellic, Frank Wien, Liqing Wu
A previous inter-laboratory study, CCQM P59, showed that there was a poor level of comparability between laboratories in circular dichroism spectroscopy. In a follow-up study reported here, we achieved our goal of demonstrating improved comparability and

Microwave Spectrum of 1,2-Propanediol

September 1, 2009
Author(s)
Francis J. Lovas, David F. Plusquellic, Brooks Pate, Justin L. Neill, Matt T. Muckle, Anthony J. Remijan
The microwave spectrum of the sugar alcohol 1,2-propanediol (CH3CHOHCH2OH) has been measured over the frequency range 6.5 GHz to 25.0 GHz with several pulsed-beam Fourier-transform microwave spectrometers. Seven conformers of 1,2-propanediol have been

Rotationally Resolved Studies of the Exciton Coupled S1/S2 Origin Regions of Diphenylmethane and the d12 Isotopologue

December 9, 2008
Author(s)
David F. Plusquellic, Kevin O. Douglass, Jaime Stearns, Nathan Pillsbury, Timothy Zwier, Christian Muller
Rotationally resolved microwave and ultraviolet spectra of jet-cooled diphenylmethane (DPM) and DPM-d^12 have been obtained in S 0, Sd1 and S2 electronic states using Fourier-transform microwave and UV laser/molecular beam spectrometers. The S0 and S1

THz Investigations of Condensed Phase Biomolecular Systems

October 8, 2008
Author(s)
Kevin O. Douglass, Hailiang Zhang, Susan K. Gregurick, Karen M. Siegrist, David F. Plusquellic
Terahertz (THz) spectroscopic investigations of crystalline dipeptide nanotubes are discussed in the frequency region from 0.6 THz (2 cm-1) to 3 THz (100 cm-1). The THz region provides access to collective modes of biomolecular systems and is therefore

Terahertz Spectroscopy of Biomolecules

December 22, 2007
Author(s)
David F. Plusquellic, Edwin J. Heilweil
Far-infrared (Terahertz or THz) spectroscopic investigations of condensed-phase biological and model organic species including substituted benzenes, amino acids, sugars, polypeptides, small proteins and DNA/RNA are reviewed. These studies reveal that for

The Microwave Spectrum of a Two-Top Peptide Mimetic: The N-Acetyl Alanine Methyl Ester Molecule

September 14, 2006
Author(s)
I Kleiner, J Demaison, David F. Plusquellic, R D. Suenram, R J. Lavrich, Francis J. Lovas, Gerald T. Fraser, Vadim V. Ilyushin
Rotational spectra of the ground torsional state of the N-acetyl alanine methyl ester molecule, a derivative of the alanine dipeptide biomimetic molecule, have been measured using a mini Fourier transform spectrometer between 10 and 20 GHz as part of a

Microwave Spectrum of the Heterodimers: CH 3 OH-CO 2 and CH 3 OH-H 2 CO

September 1, 2006
Author(s)
Vadim V. Ilyushin, Francis J. Lovas, David F. Plusquellic
Molecular complexes, dimers and heterodimers, often show interesting structures, large amplitude internal motions and orientations for reaction coordinates. These properties were the motivations for the current study of the rotational spectra of the

Microwave Spectrum and Structure of Methyl Phosphonic Difluoride

January 2, 2006
Author(s)
R D. Suenram, Francis J. Lovas, David F. Plusquellic, M W. Elizy, J M. Lochner, J O. Jensen, A C. Samuels
The rotational spectrum of methyl phosphonic difluoride has been reinvestigated using a pulsed-molecular-beam Fabry-Perot cavity microwave spectrometer. The enhanced resolution of the Fourier transform microwave (FTMW) spectrometer (compared to the