An ab initio treatment on some isomeric structures of a small pseudocyclacene

Türker, Burhan Lemi
At the level of 6-31G (RHF) type ab initio calculations, some structures isomeric with the pseudocyclacene are considered. Some structures have the same or almost the same energy values. This situation causes the pseudocyclacene structure to be vague at the level of calculations.


A theoretical study on certain iron-sulfur and iron-selenium clusters
Turker, L; Erkoç, Şakir (Elsevier BV, 2003-04-04)
[Fe4S4], [Fe4S3Se] and [Fe4Se4] type iron-sulfur and iron-sulfur-selenium and iron-selenium clusters, all having four cysteinyl moieties as ligands have been considered for ab initio quantum chemical analysis at the level of 6-31G (RHF). All the structures are found to be stable and the stability of Se containing structures increases as the number of Se atoms increases. The inter frontier molecular orbital energy gaps and the HOMO energies follow the same order.
A perturbative treatment for the bound states of the Hellmann potential
Ikhdair, Sameer M.; Sever, Ramazan (Elsevier BV, 2007-05-14)
A new approximation formalism is applied to study the bound states of the Hellmann potential, which represents the superposition of the attractive Coulomb potential -a/r and the Yukawa potential bexp(-delta r)/r of arbitrary strength h and screening parameter delta. Although the analytic expressions for the energy eigenvalues E(n,l) yield quite accurate results for a wide range of n, f in the limit of very weak screening, the results become gradually worse as the strength b and the screening coefficient 6 i...
The ortho- to meta- isomerization of dicarba-closo-dodecaborane
Türker, Burhan Lemi (Elsevier BV, 2003-08-01)
By means of AMI(RHF) type semiempirical quantum chemical calculations, the conversion of ortho- dicarba-closododecaborane to its meta- isomer is throughly investigated by considering two intermediate structures previously proposed.
Pseudocyclacene electronic circuits - an ab initio treatment
Türker, Burhan Lemi (Elsevier BV, 2003-01-03)
Pseudocyclacene structure has been considered for ab initio type calculations (3-21G and 6-31G). The unrestricted Hartree-Fock approach was used throughout the calculations. The pseudocyclacene structure having cyclobutadienic peripheral circuits is estimated to be more stable by 3-21G and 6-31G type calculations. Although, 3-21G type calculations predict discernible stability of transoid form over cisoid form, the 6-31G type cannot differentiate in between these two forms. On the other hand, the total ener...
Structural and electronic properties of guanine and guanosine
Erkoc, F; Erkoç, Şakir (Elsevier BV, 2002-08-16)
The structural and electronic properties of guanine and guanosine have been investigated theoretically by performing semi-empirical and ab initio molecular orbital theory calculations. The geometry of the systems have been optimized considering the semi-empirical molecular orbital theory at the level of Austin model 1, and the electronic properties of the systems have been calculated by ab initio restricted Hartree-Fock with including full MP2 correlation correction in their ground state.
Citation Formats
B. L. Türker, “An ab initio treatment on some isomeric structures of a small pseudocyclacene,” JOURNAL OF MOLECULAR STRUCTURE-THEOCHEM, pp. 109–113, 2003, Accessed: 00, 2020. [Online]. Available: