An ab initio quantum chemical investigation of TOMS nmr SHIELDING TENSORS IN Adenine-thymine, Adenine-uracil, Guanine-Cytosine & uracil-quartet: comparison between theoretical and experimental results

an ab initio quantum chemical investigation of toms nmr shielding tensors in adenine-thymine, adenine-uracil, guanine-cytosine & uracil-quartet: comparison between theoretical and experimental results

we have evaluated the nmr shielding tensors for a:t,g:c,a:u in watson-crick, and u-quartet. we have computed nmr shielding tensors at b31yp level by using 6-31g(d) basis set. we have compute anisotropy and asymmetry in a:t,g:c,a:u and u-quartet. the nmr shielding tensors were calculated using the giao method. the natural bonding orbital analysis (nbo) were performed. nbo calculation have been ...

Surface-Enhanced Hyper-Raman Spectra of Adenine, Guanine, Cytosine, Thymine, and Uracil

Using picosecond excitation at 1064 nm, surface-enhanced hyper-Raman scattering (SEHRS) spectra of the nucleobases adenine, guanine, cytosine, thymine, and uracil with two different types of silver nanoparticles were obtained. Comparing the SEHRS spectra with SERS data from the identical samples excited at 532 nm and with known infrared spectra, the major bands in the spectra are assigned. Due ...

Ab initio study & Density functional investigational of Adenine & Thymine; Comparison of primitive Gaussian and NBO calculation

We have performed quantum-chemical ab initio in various basis sets at the Hartree-Fock andB3LYP levels for Adenine and Thymine with the program GAUSSIAN98. The Dipole,Quadrupole, Octapole and Hexadecapole moments and primitive in nine basis sets for thesemolecules are presented. The most stabilized forms of these molecules are observed in 6-311++G** basis set. We have evaluated coefficient hybr...

Hydration energy of Adenine, Guanine, Cytosine and Thymine : Monte Carlo simulation

The hydration of biomolecules is vitally important in molecular biology, so in this paper thesolvation energy and radial distribution function of DNA bases have been calculated by theMonte Carlo simulation.The geometries of isolated Adenine, Guanine, Cytosine, and Thyminehave been optimized using 6-31+G(d,p) basis function sets. These geometries then will be used inthe Monte Carlo calculation o...

Adenine Uracil Guanine: An Exploration of Certainty in Science

Quantum-chemical ab initio study on the adenine-difluorotoluene complex--a mimic for the adenine-thymine base pair.

Recent experiments have shown that difluorotoluene (F), a nonpolar isostere for thymine (T), codes efficiently and specifically for adenine (A) in DNA replication. F has almost the same shape as thymine but it is unable to form conventional hydrogen bonds with adenine. Therefore, it has been claimed that not hydrogen bonding but shape complementary may be important for the selection of the corr...