Members: G. Theodorakopoulos, I. D. Petsalakis, E. D. Simandiras, N.N. Lathiotakis
Research fellows: D. Tzeli, I. Thanopoulos, I.S.K. Kerkines

Three broad aspects of research activities are pursued:

1. Electronic structure calculations on free molecules, molecules in confined space, molecules adsorbed on surfaces, clusters and nano-hybrids, with emphasis on excited electronic states and processes.
(G. Theodorakopoulos, I. D. Petsalakis, D. Tzeli, I. Thanopoulos, I.S.K. Kerkines)

Quantum mechanical methods are employed to carry out research in molecular physics and computational chemistry. Large-scale ab initio configuration interaction methods as well as advanced theoretical methods developed by the group (complex coordinate rotation methods, multi-channel quantum defect theory), are employed to study various processes in excited electronic states and highly excited electronic states of small molecules and excimers, including spectral perturbations, predissociation and vibrational autoionization.  Existing implementations of density functional theory (DFT) and time-dependent density functional theory (TDDFT), are employed to calculate energy transfer and charge transfer processes in   carbon nanohybrids, push-pull chromophores and Chemical sensors, to calculate reaction energies and spectra of molecules in cages as well as to perform quantum control on nanoscale systems.  
The results of these high quality computations are related to materials design, nanotechnology and nanodevices, photovoltaics and bio-applications as well as spectroscopy, astrophysics and the chemistry of the interstellar space and upper atmosphere.  

Main current research activities:

(i) Charge-transfer and energy transfer in donor-acceptor systems: Functionalized carbon nanohorns and fullerene hybrids , organic electronics and Chemical sensors. Our approach includes the formulation of simple rules for the design of donor-acceptor intramolecular charge transfer (ICT) systems and for photoinduced electron transfer (PET) systems, based on orbital level diagrams of the separate donor and acceptor moieties.

(ii) Chemistry in confined space: Structure and properties of molecules inside cages and nanotubes. Calculations on the reaction energies of hydrogen bonded dimers in cages and the emission of trans-stilbene in cages explain experimental findings.

(iii) Investigations of structure and processes in excited and highly excited states of small molecules. Recent investigations focused on the coherent  oscillatory femtosecond dynamics in multichannel photodynamics of NO₂ as well as the electronic states of CF relevant to the dissociative recombination of CF+.
 

Other research activities:

(i) Group III metal nitrides and their chemisorption on Si(111). Formation of thin films, nanowires and nanoclusters.

(ii) Nanoscale patterning on a Si(111) surface

(iii) Development of molecular electronic devices based on porphyrin derivatives

(iv) Methodological advances on the dynamics of open quantum systems

The activity ''Quantum Control'' is financed through the FP7-PEOPLE- IRG-2008 (2008-2012) programme.  Collaborations in the activity on “Chemical Sensors” are financed through the programme NATO PST/CLG.977379, 2009-2012)

2. Theoretical studies of amorphous inorganic systems and of transition metal clusters
(E. D. Simandiras)

Current activities:

(iv) Structure, spectroscopy and reactions of transition metal clusters with an interest in catalysis
(v) The local structure of glasses using large ab initio models

3. Development and application of Density and Density-Matrix Functional approaches for the treatment of electronic correlations in molecular and periodic systems (N. N. Lathiotakis).

A) Development:

(i) Reduced Density Matrix Functional Theory: introduction of new functionals, study of their properties and evaluation of their performance in the prediction of properties of molecules and solids.

(ii) Treatment of problems in Optimized Effective Potential (OEP) method and extension to RDMFT.

B) Applications of density functional approaches to:

(i) Structural, elastic and electronic properties of graphene based nanostructures.

(ii) Interaction of magnetic impurities in ZnO.

(a) azafullerene inside a nanotube                              (b) encapsulated carboxylic acid dimer

(c) encapsulated stilbene in the ground and first excited singlet electronic states

(d) Potential energy curves of the ground and excited (²Π) states of CF

(e) orbital level diagram for Intramolecular Electron Transfer

   
      (f) quantum control                                                              (g) photoinduced charge transfer

(h) porphyrin-nanohorn hybrid                                                   (i) dicarboxylic acid sensor