Electromagnetic radiation in the THz region of the spectrum is capable of probing the “weak forces” in a number of different solvent, polymer and biopolymer systems.  These forces include hydrogen-bonding, electrostatic, ionic, and van der Waal interactions which have energy that is equivalent to the thermal energy (kT) available at room temperature.  Changes in the weak interactions in these systems, which occur on the timescale of about 1 picosecond or equivalently a frequency of 1 THz (terahertz), govern the fast conformational dynamics that are associated with processes such as biomolecule-ligand binding and recognition, segmental and terminal chain dynamics connected with phase transition in polymer systems, and collective atomic motions necessary for initiating specific chemical reaction pathways.   Given that these types of low energy fluctuations are poorly understood, their study with THz or far-infrared spectroscopy offers the possibility of providing new insight into the onset of many fundamental chemical and biological processes.

My research is aimed at developing a deeper understanding about the fast, low frequency microscopic interactions taking place in polymer and biopolymer systems with THz and mid-infrared spectroscopy.  Development of novel optical and imaging methods with infrared light is utilized to address fundamental questions regarding molecular level processes.  This is an interdisciplinary effort strongly centered in chemical physics but spanning areas of condensed matter physics, materials science, and biological physics. 

Selected Publications

K.N. Woods, H.-Y. N. Holman, H. Wiedemann,  “Solvent induced fluctuations and the collective librational dynamics of lysozyme studied by THz and mid-infrared spectroscopy”, (J. Chem. Phys. Submitted 12/07 ).

K.N. Woods, S.A. Lee, H.-Y. N. Holman, and H. Wiedemann, “The effect of solvent dynamics on the low frequency collective motions of DNA in solution and unoriented films”, (J. Chem. Phys. 124 (2006) 224706).

K.N. Woods and H. Wiedemann, “The influence of chain dynamics on the far-infrared spectrum of liquid methanol-water mixtures”, J. Chem. Phys. 123 (2005) 134507.

K.N. Woods and H. Wiedemann, “The influence of chain dynamics on the far-infrared spectrum of liquid methanol”, J. Chem. Phys. 123 (2005) 134506.

 K.N. Woods and H. Wiedemann, “The relationship between dynamics and structure in the far-infrared absorption spectrum of liquid water”, Chem. Phys. Lett. 393 (2004) 159.

C. Settakorn, M. Hernandez, K.N. Woods, and H. Wiedemann, “Coherent far-infrared radiation from electron bunches”, SLAC-PUB-7813 (1999)