Sökning: "NATURVETENSKAP Kemi Fysikalisk kemi Kemisk fysik"

Visar resultat 1 - 5 av 67 avhandlingar innehållade orden NATURVETENSKAP Kemi Fysikalisk kemi Kemisk fysik.

1. 1. The Role of Molecular Heterogeneity in the Structural Dynamics of Aqueous Solutions

   Författare :Sharon Berkowicz; Fivos Perakis; Giulio Monaco; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Water; Aqueous solutions; X-ray scattering; X-ray photon correlation spectroscopy; Dynamic light scattering; kemisk fysik; Chemical Physics;

   Sammanfattning : The liquid-liquid critical point hypothesis suggests that liquid water exists in two liquid states with different local structures, so-called high- and low-density liquid (HDL, LDL). At ambient pressure water locally fluctuates between these two states, with the fluctuations becoming more pronounced as the liquid is supercooled. LÄS MER

3. 2. Electric Fields for Surface Design and Chemical Analysis

   Författare :Christian Ulrich; Fredrik Björefors; Ingemar Lundström; Tautgirdas Ruzgas; Linköpings universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Electric fields; Surface design; Chemical analysis; Bipolar electrodes; Impedance spectroscopy; Electrochemistry; Elektrokemi; Chemical physics; Kemisk fysik; Physical chemistry; Fysikalisk kemi; Surface and colloid chemistry; Yt- och kolloidkemi;

   Sammanfattning : This thesis deals with the use of electric fields for evaluation and control of chemical systems. An electric field can result in the flow of charge across an interface between a metal and a solution, by means of chemical reactions. This interplay between electricity and chemistry, i.e. LÄS MER

4. 3. Single and Accumulative Electron Transfer – Prerequisites for Artificial Photosynthesis

   Författare :Susanne Karlsson; Leif Hammarström; Hans-Christian Becker; Devens Gust; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Artificial photosynthesis; Photoinduced charge separation; Electron transfer; Energy transfer; Accumulative electon transfer; Donor-acceptor; Ruthenium; Linear arrays; Chemical physics; Kemisk fysik; Kemi med inriktning mot kemisk fysik; Chemistry with specialization in Chemical Physics;

   Sammanfattning : Photoinduced electron transfer is involved in a number of photochemical and photobiological processes. One example of this is photosynthesis, where the absorption of sunlight leads to the formation of charge-separated states by electron transfer. LÄS MER

5. 4. The Role of Molecular Heterogeneity in the Structural Dynamics of Aqueous Solutions

   Författare :Sharon Berkowicz; Fivos Perakis; Anders Hedqvist; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; kemisk fysik; Chemical Physics;

   Sammanfattning : Aqueous solutions constitute the basis of life, yet their complex and anomalous nature is far from well-understood. Transient molecular ordering gives rise to microscopic spatial liquid heterogeneities and fluctuations which are believed to play a key role in biochemical processes as well as in pure water, the latter of which could fundamentally alter our view on water as life's solvent. LÄS MER

7. 5. Proton-Coupled Electron Transfer from Hydrogen-Bonded Phenols

   Författare :Tania Irebo; Leif Hammarström; James M. Mayer; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Proton-coupled electron transfer; phenol oxidation; hydrogen bonds; artificial photosynthesis; promoting vibrations; proton transfer; laser flash-quench; transient absorption.; Physical chemistry; Fysikalisk kemi; Fysikalisk kemi; Physical Chemistry;

   Sammanfattning : Proton-coupled electron transfer (PCET) is one of the elementary reactions occurring in many chemical and biological systems, such as photosystem II where the oxidation of tyrosine (TyrZ) is coupled to deprotonation of the phenolic proton. This reaction is here modelled by the oxidation of a phenol covalently linked to a Ru(bpy)32+-moitey, which is photo-oxidized by a laser flash-quench method. LÄS MER