Community Medicine

This departmental history was written on the occasion of the UND Centennial in 1983.https://commons.und.edu/departmental-histories/1010/thumbnail.jp

Liquid crystals as amplifiers of molecular chirality

Bepaalde organisch chemische moleculen komen voor in twee vormen die volledig identiek zijn op één eigenschap na. De twee vormen zijn namelijk spiegelbeelden. Dat onderscheid wordt in de chemie chiraliteitgenoemd. Rienk Eelkema onderzocht hoe je chiraliteit kunt gebruiken voor het ontwikkelen van nieuwe materialen. Daarbij keek hij met name naar het gedrag van zogenaamde moleculaire motoren en schakelaars in vloeibaar kristallijnen films. De resultaten van dit onderzoek werden eerder dit jaar in Nature gepubliceerd (zie persbericht nr. 26 op de RUG website)

Large tunable image-charge effects in single-molecule junctions

The characteristics of molecular electronic devices are critically determined by metal-organic interfaces, which influence the arrangement of the orbital levels that participate in charge transport. Studies on self-assembled monolayers (SAMs) show (molecule-dependent) level shifts as well as transport-gap renormalization, suggesting that polarization effects in the metal substrate play a key role in the level alignment with respect to the metal's Fermi energy. Here, we provide direct evidence for an electrode-induced gap renormalization in single-molecule junctions. We study charge transport in single porphyrin-type molecules using electrically gateable break junctions. In this set-up, the position of the occupied and unoccupied levels can be followed in situ and with simultaneous mechanical control. When increasing the electrode separation, we observe a substantial increase in the transport gap with level shifts as high as several hundreds of meV for displacements of a few \aa ngstroms. Analysis of this large and tunable gap renormalization with image-charge calculations based on atomic charges obtained from density functional theory confirms and clarifies the dominant role of image-charge effects in single-molecule junctions

Dynamics of hydroxide-ion-driven reversible autocatalytic networks

An autocatalytic reaction network is designed utilising the interplay of hydroxide concentration dependent reactions and acid–base equilibria of imine hydrolysis