1 / 2

Per

Exploring the interaction between two molecular chains James S. Brooks, Florida State University, DMR 0602859. a). b).

dwight
Download Presentation

Per

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Exploring the interaction between two molecular chainsJames S. Brooks, Florida State University, DMR 0602859 a) b) Perylene is a planar organic molecule which stacks to make a conducting chain. Pt(mnt)2 is also a planar molecule which stacks as an insulating paramagnetic chain where the Pt ion carries a spin ½ moment. Together, they make the organic conductor Per2[Pt(mnt)2] that when cooled below 8 K, undergoes a dramatic transition where the Peryelene chain becomes an insulator and the Pt(mnt)2 chain becomes non-magnetic (spin singlet). These two transitions, known as Peierls (or charge density wave – “CDW”) and Spin-Peierls respectively, are simultaneous, indicating a strong interaction between the physics of each chain. As part of her PhD work, Liz Prettner is using proton (1H on Perylene) and platinum (195Pt on Pt(mnt)2) NMR to follow the nature of this coupling in each chain vs. temperature and magnetic field. Pt Per c) Figure Caption: a) Crystal structure of Per2[Pt2(mnt)2] showing the perylene and Pt(mnt)2 chain directions (protons in pink, Pt in orange). b) NMR experiment showing acquisition of a 1H spin-echo signal. c) Comparison of NMR data with mean-field theory and transport descriptions of the T-B phase diagram. 195Pt NMR indicates that the two chains are very strongly coupled even at high fields, but that the spin Peierls chain is starting to break down, causing a dephasing of the hyperfine fields near the phase boundary. 1H NMR to 30 T is planned to investigate the chain coupling in great detail.

  2. Empowering K-5 teachers with scientific contentJames S. Brooks, Florida State University, DMR 0602859 The participation in outreach activities by someone who practices science on a daily basis adds value and credibility to the process. The PI has spent considerable time in the development of instructional materials (presentations, notes, and hands-on activities) aimed and increasing the competence and confidence in science content (as opposed to “make and take” lesson plans) for K-5 teachers in the Florida elementary school system. Time, patience and simplicity are essential in this process. The pictures are from a workshop on “Matter and Energy” in July, 2010. a) b) c) d) Caption: a) Based on a simple Archimedes experiment by the PI, the Queen learns that the gold crown, a gift from the King, is aluminum. b) Is air more dense than CO2? c) Probing a non-Newtonian fluid. d) The fundamentals of electrical circuits.

More Related