Quantum chemical studies on hydrogen adsorption in carbon-based model systems: role of charged surface and the electronic induction effect

2008 ◽  
Vol 10 (38) ◽  
pp. 5832 ◽  
Author(s):  
K. Srinivasu ◽  
K. R. S. Chandrakumar ◽  
Swapan K. Ghosh
Keyword(s):  
Quantum Chemical ◽  
Hydrogen Adsorption ◽  
Model Systems ◽  
Induction Effect ◽  
Charged Surface ◽  
Chemical Studies ◽  
Quantum Chemical Studies ◽  
Carbon Based

Quantum chemical studies on the role of residues in calcium ion binding to Calmodulin

2014 ◽  
Vol 605-606 ◽  
pp. 103-107 ◽  
Author(s):  
Samapan Sikdar ◽  
Mahua Ghosh ◽  
Molly De Raychaudhury ◽  
J. Chakrabarti
Keyword(s):  
Calcium Ion ◽  
Quantum Chemical ◽  
Ion Binding ◽  
Chemical Studies ◽  
Quantum Chemical Studies ◽  
Calcium Ion Binding

The role of pyrimidine nucleobase excimers in DNA photophysics and photoreactivity

2009 ◽  
Vol 81 (9) ◽  
pp. 1695-1705 ◽  
Author(s):  
Israel González-Ramírez ◽  
Teresa Climent ◽  
Juan José Serrano-Pérez ◽  
Remedios González-Luque ◽  
Manuela Merchán ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Quantum Chemical ◽  
Electronic States ◽  
Conical Intersections ◽  
Chemical Studies ◽  
Quantum Chemical Studies ◽  
Dna Nucleobases ◽  
Surface Crossings

Quantum chemical studies using the accurate CASPT2//CASSCF procedure show that π-stacked interactions in biochromophores such as pyrimidine (Pyr) DNA/RNA nucleobases pairs yield excimer-like situations which behave as precursors of processes like charge transfer (CT) or photoreactivity and are the source of the emissive properties in DNA. Examples are the CT between adjacent DNA nucleobases in a strand of oligonucleotides and the photodimerization taking place in cytosine (C) pairs leading to cyclobutanecytosine (CBC) mutants. These processes take place through nonadiabatic photochemical mechanisms whose evolution is determined by the presence and accessibility of conical intersections (CIs) and other surface crossings between different electronic states.

scholarly journals Quantum chemical studies of protein structure

2004 ◽  
Vol 360 (1458) ◽  
pp. 1347-1361 ◽  
Author(s):  
Eric Oldfield
Keyword(s):  
Protein Structure ◽  
Quantum Chemical ◽  
Chemical Shifts ◽  
Model Systems ◽  
Charge Densities ◽  
Electrostatic Properties ◽  
Field Gradients ◽  
Quantum Chemical Methods ◽  
Chemical Studies ◽  
Quantum Chemical Studies

Quantum chemical methods now permit the prediction of many spectroscopic observables in proteins and related model systems, in addition to electrostatic properties, which are found to be in excellent accord with those determined from experiment. I discuss the developments over the past decade in these areas, including predictions of nuclear magnetic resonance chemical shifts, chemical shielding tensors, scalar couplings and hyperfine (contact) shifts, the isomer shifts and quadrupole splittings in Mössbauer spectroscopy, molecular energies and conformations, as well as a range of electrostatic properties, such as charge densities, the curvatures, Laplacians and Hessians of the charge density, electrostatic potentials, electric field gradients and electrostatic field effects. The availability of structure/spectroscopic correlations from quantum chemistry provides a basis for using numerous spectroscopic observables in determining aspects of protein structure, in determining electrostatic properties which are not readily accessible from experiment, as well as giving additional confidence in the use of these techniques to investigate questions about chemical bonding and chemical reactions.

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