A THEORETICAL STUDY OF POTENTIAL ENERGY CURVES AND TRANSITION DIPOLE MOMENT OF THE CO+ ION

Ab initio calculations were performed for several doublet states of the CO+ cation using the multi reference single and double excitation configuration-interaction (MRDCI) method. The dipole transition matrix elements for 2Σ+ and 2Π states have been calculated and the molecular properties of the CO+ cation have been studied in detail. The calculated results show good agreement of with available experimental measurements as well as other theoretical results

ELECTRON CAPTURE CROSS SECTIONS IN COLLISIONS OF 3He2+ IONS WITH CO MOLECULE

The single electron capture process in collisions of 3He2+ ions with CO molecule have been studied theoretically using semiclassical collision methods in which the adiabatic potentials and nonadiabatic couplings were obtained using the multireference single- and double-excitation configuration-interaction (MRDCI) approach. The partial and total single electron capture cross sections have been obtained for energies between 0.6 to 6 keV. The calculated cross sections depend very sensitively on the molecular configuration, thus revealing a strong steric effect. The calculated single electron capture cross sections are in good agreement with the experimental measurements of Kusakabe et al. [Phys. Rev. A 73, 022706 (2006)] and Čadež et al. [J. Phys. B: At. Mol. Opt. Phys. 35, 2515 (2002)]. The present study provides a theoretical basis for the experimental measurements by interpreting the detailed collision dynamics

A COMPUTATIONAL STUDY OF STABILITY AND TRANSITION DIPOLE MOMENT OF SEVERAL LOW LYING ELECTRONIC STATES OF THE CO MOLECULE

The potential energy surface for the X 1∑+ , A1 Ï€, D´1∑+, B1∑+,E1Ï€,C1∑+ and C´1∑+  of CO molecule have been calculated using the multiconfiguration self- consistent field and configuration interaction methods. The calculations have been carried out at 84 internuclear distances from 1.4 to 7 a0 by the aug-cc-pVQZ basis set, the spectroscopic constants also are found to be in good agreement with the experimental data. Some states also have double potential i.e. the second and third state which correlates to the B 1∑+ and C 1∑+ Rydberg states at small internuclear distance (Re). The inner well corresponds to B 1∑+ and C 1∑+ while the outer one corresponds to D´1∑+ and C´1∑+.Â

A TIME-DEPENDENT STUDY OF ELECTRONIC SPECTROSCOPY OF 1, 3, 5-TRANS-HEXATRIENE MOLECULE

The electronic absorption spectrum, the relative Raman intensities upon 0-0 excitation, and the resonance Raman excitation profiles of trans-l, 3, 5-hexatriene in the region of the 1 1Bu à 1 1Ag transition are analyzed on the basis of the structures and vibrational force fields obtained from ab initio molecular orbital (MO) calculations. Our implementation of the time-dependent theory for the fitting of experimental spectra and the simulation of model spectra as well as the quantum mechanical calculation of the model parameters is discussed. The implementation covers all electronic structure approaches which are able to deliver ground- and excited-state energies and transition dipole moments. As a test case we discuss the well-known case of the strongly allowed 1 1Agà1 1Bu transition in 1, 3, 5- trans-hexatriene in detail using method ranging from simple single-reference treatments to elaborate multi-reference electronic structure approaches

THEORETICAL MODELLING OF NUCLEAR RESONANCE VIBRATIONAL SPECTRA OF COMPLEX MOLECULES

The vibrational spectrum of an   complex was calculated by Density functional Theory (DFT) frequency calculation and are optimized using the BP86 or B3LYP functionals and TZVP basis. Using a DFT approach, the normal mode composition factors and vibrational frequencies have been determined, and the nuclear resonance vibrational spectroscopy (NRVS) spectra have been fitted and simulated. The strong correlation between the experimental and calculated spectra allows for a clear interpretation of the NRVS data. These data provide important spectroscopic markers for high-valent Fe species and demonstrate the utility of this technique for the determination of Fe dynamics