Sökning: "first principles simulations"

Visar resultat 1 - 5 av 117 avhandlingar innehållade orden first principles simulations.

1. 1. First principles simulations of electron transport at the molecule-solid interface

   Författare :Hao Ren; Yi Luo; Nicolás Lorente; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; first principles; electron transport; solid surface; inelastic electron tunneling; Quantum chemistry; Kvantkemi;

   Sammanfattning : In this thesis I concentrate on the description of electron transport properties of microscopic objects, including molecular junctions and nano junctions, in particular, inelastic electron tunneling in surface-adsorbate systems are examined with more contemplations. Boosted by the rapid advance in experimental techniques at the microscopic scale, various electric experiments and measurements sprung up in the last decade. LÄS MER

3. 2. First Principles Studies of Carbon Based Molecular Materials

   Författare :Bin Gao; Yi Luo; Piero Decleva; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; first principles simulations; carbon based molecular materials; X-ray spectroscopies; Theoretical chemistry; Teoretisk kemi;

   Sammanfattning : The aim of this thesis was to investigate carbon based molecular materials at first principles levels. Special attention has been paid to simulations of X-ray spectroscopies, including near edge X-ray absorption fine structure (NEXAFS), X-ray photoelectron, and X-ray emission spectroscopy, which can provide detailed information about core, occupied and unoccupied molecular orbitals of the systems under investigation. LÄS MER

4. 3. High Resolution Tip-Enhanced Raman Images of Single Molecules from First Principles Simulations

   Författare :Zhen Xie; Yi Luo; Filippo De Angelis; KTH; []
   Nyckelord :First Principles; Tip-Enhanced Raman Images; light-matter interactions at the nanoscale; Teoretisk kemi och biologi; Theoretical Chemistry and Biology;

   Sammanfattning : With the precise control of spatially confined plasmon (SCP), tip-enhanced Raman spectroscopy (TERS) has achieved sub-nanometer resolution, leading to the chemical and physical characterization of the single molecule by optical Raman images. In the high resolution TERS measurements, the SCP spatial distribution generates the position-dependent Raman images. LÄS MER

5. 4. Materials Design from First Principles : stability and magnetism of nanolaminates

   Författare :Martin Dahlqvist; Johanna Rosén; Nicola Spaldin; Linköpings universitet; []
   Nyckelord :;

   Sammanfattning : In this thesis, first-principles calculations within density functional theory are presented, with a principal goal to investigate the phase stability of so called Mn+1AXn (MAX) phases. MAX phases are a group of nanolaminated materials comprised of a transition metal (M), a group 12-16 element (A), and carbon or nitrogen (X). LÄS MER

7. 5. Effects of disorder in metallic systems from First-Principles calculations

   Författare :Christian Asker; Igor Abrikosov; Jörg Neugebauer; Linköpings universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Iron; Nickel; Magnesium; Manganese; Molybdenum; Zirconium; Elastic Constants; High pressure; Earth s core; Density-functional theory; Ab-initio; First-Principles; Core-level shifts; Molecular Dynamics; Phonons; Dynamical Instability; Condensed matter physics; Kondenserade materiens fysik; Computational physics; Beräkningsfysik;

   Sammanfattning : In this thesis, quantum-mechanical calculations within density-functional theory on metallic systems are presented. The overarching goal has been to investigate effects of disorder. In particular, one of the properties investigated is the bindingenergy shifts for core electrons in binary alloys using different theoretical methods. LÄS MER