A theoretical study of the B′2Σ+–X2Σ+ band system in MgH and MgD

1979 ◽  
Vol 57 (8) ◽  
pp. 1178-1184 ◽  
Author(s):  
M. L. Sink ◽  
A. D. Bandrauk
Keyword(s):  
Dipole Moment ◽  
Theoretical Study ◽  
Transition Probabilities ◽  
Band System ◽  
Dipole Moments ◽  
Electronic States ◽  
Oscillator Strengths ◽  
Moment Functions ◽  
Condon Factors ◽  
Franck Condon

Ab initio Cl calculations of the transition moment for the B′2Σ+–X2Σ+ transition in MgH are reported. Theoretical values for the Franck–Condon factors, band strengths, band oscillator strengths, and transition probabilities have been computed for MgH and MgD. An analysis of our results for this system predicts many bands to be observable which have not yet been identified. Dipole moment functions and vibrationally averaged dipole moments are given for the X2Σ+, A2Π, and B′2Σ+ electronic states.

The spectroscopy of H2CS. 1. CS stretch potential curves for singlet states of planar H2CS, obtained by ab initio multireference CI methods

1995 ◽  
Vol 73 (1-2) ◽  
pp. 18-34 ◽  
Author(s):  
M. R. J. Hachey ◽  
F. Grein
Keyword(s):  
Dipole Moments ◽  
Oscillator Strengths ◽  
Excitation Energies ◽  
Valence States ◽  
Singlet States ◽  
Symmetry Species ◽  
Condon Factors ◽  
Combination Modes ◽  
Franck Condon ◽  
Potential Curves

For planar H2CS, (C2ν), the CS stretch potential curves were obtained for the four to six lowest singlet states of each symmetry species by using multireference CI methods. Included were the (n, 4s), (n, 4p), (n, 3d), (π, 4s), and (π, 4p) Rydberg as well as the (n, π*), (π, π*), (σ, π*), (n, σ*), (n0, π*2), and (nπ, π*2) valence states. Vertical and adiabatic excitation energies, equilibrium CS distances, vibrational frequencies for the CS stretching mode, dipole moments, oscillator strengths, and Franck–Condon factors were evaluated and found to be in good agreement with known experimental data. The role of the 1(π, π*) state that diabatically crosses all 1A1 states, including the n2 ground-state configuration, causing many interactions with other states, has been given special attention. The following reassignments and predictions are of interest. (i) A switch of Ẽ and [Formula: see text], with 1A1(n, 4py) corresponding to the Ẽ bands and 1B2(n, 4pz) corresponding to the [Formula: see text] bands is suggested, based on the energetic ordering. (ii) Because of strong Franck–Condon factors, hot bands are suggested to play an important role in the analysis of the CS stretch progression of [Formula: see text]. (iii) The [Formula: see text] system, only studied in low resolution, is predicted to have high intensity and be perturbed due to the crossing of (π, π*) with (n, 4py) in the vertical region. The CS stretch bands should be observable. (iv) Observed combination modes in the [Formula: see text] system may be due to vibronic mixing of (π, π*) with (σ, π*).

Abinitio SCF and MRD-CI description of the A2A′ – X2A″ transition of the as yet unknown HNCl molecule

1985 ◽  
Vol 63 (11) ◽  
pp. 3264-3268 ◽  
Author(s):  
Britta L. Schürmann ◽  
Robert J. Buenker
Keyword(s):  
Ground State ◽  
Mode Coupling ◽  
Vibrational Analysis ◽  
Electronic States ◽  
Oscillator Strengths ◽  
Fundamental Frequencies ◽  
Condon Factors ◽  
Franck Condon ◽  
Linear Geometry ◽  
Made In

Abinitio potential curves of the X2A″ ground state and the first excited A2A′ state (2Π in linear geometry) of HNCl are calculated employing multi-reference single- and double-excitation configuration interaction in order to aid in the search for this system experimentally. A vibrational analysis (frequencies and Franck–Condon factors) of the A2A′ – X2A″ transition is undertaken by neglecting coupling between the various modes. Diagonal and off-diagonal force constants together with the fundamental frequencies have been calculated by including mode coupling for both electronic states, and oscillator strengths and radiative lifetimes are also obtained. Comparison with theoretical and experimental results for other isovalent systems is also made in order to establish trends in this group of HAB systems.

Long-range potentials and dipole moments of the CO electronic states converging to the ground dissociation limit

2020 ◽  
Vol 22 (21) ◽  
pp. 12058-12067
Author(s):  
Vladimir G. Ushakov ◽  
Vladimir V. Meshkov ◽  
Aleksander Yu. Ermilov ◽  
Andrey V. Stolyarov ◽  
Iouli E. Gordon ◽  
...  
Keyword(s):  
Perturbation Theory ◽  
Dipole Moment ◽  
Potential Energy ◽  
Long Range ◽  
First Principles ◽  
Dipole Moments ◽  
Electronic States ◽  
Dissociation Limit ◽  
Moment Functions ◽  
Range Perturbation

The potential-energy and dipole-moment functions for six electronic states are obtained both analytically, in the framework of long-range perturbation theory, and numerically, by using first-principles methods.

Theoretical investigation of the electronic structure and spectra of sulfur monoiodide cation, SI+

2020 ◽  
Vol 98 (12) ◽  
pp. 806-813
Author(s):  
Gabriel Fernando de Melo ◽  
Fernando R. Ornellas
Keyword(s):  
Dipole Moment ◽  
Transition Probabilities ◽  
Dipole Moments ◽  
Transition Dipole Moment ◽  
Theoretical Treatment ◽  
Transition Dipole ◽  
Dissociation Energies ◽  
Moment Functions ◽  
High Level ◽  
First Time

A manifold of singlet, triplet, and quintet electronic states of the sulfur monoiodide cation (SI+) correlating with the two lowest-lying dissociation channels is characterized theoretically at a high level of theoretical treatment (SA-CASSCF/MRCI+Q/aug-cc-pV5Z) for the first time. Potential energy curves, also including the effect of spin-orbit couplings, are constructed and the associated spectroscopic parameters and dissociation energies determined. As to the molecular polarity, we computed the dipole moment as a function of the internuclear distance and the associated vibrationally averaged dipole moments. Transition dipole moment functions were also constructed, and transition probabilities, as expressed by the Einstein coefficients for spontaneous emission, were evaluated for selected pairs of states that we identify as more easily accessible to experimental investigation. An analysis of the bonding in this system is also presented. Together with previous studies on neutral and cationic sulfur-monohalides, one has a comprehensive view of this series of molecules.

Franck-Condon Factors and R-Centroids for the Band System a1Π-X1Σ+ of the InH Molecule

1993 ◽  
Vol 58 (7) ◽  
pp. 1491-1494 ◽  
Author(s):  
Narayanan Rajamanickam ◽  
Thangamariappan Murali ◽  
Thangasamy Sakthivel ◽  
Manuel Fernandez Gomez ◽  
Juan Jesus Lopez Gonzalez
Keyword(s):  
Numerical Integration ◽  
Transition Probabilities ◽  
Band System ◽  
Vibrational Transition ◽  
Integration Procedure ◽  
Condon Factors ◽  
Franck Condon ◽  
Suitable Potential ◽  
Numerical Integration Procedure

The Franck-Condon factors (vibrational transition probabilities) and r-centroids have been evaluated by a numerical integration procedure for the bands of the a3Π1-X1Σ+ system of the InH molecule using a suitable potential.

THEORETICAL TRANSITION PROBABILITIES FOR THE $\tilde{A}^{2}A_{1} -\tilde{X}^{2}B_{1}$ SYSTEM OF H2O+ AND D2O+ AND RELATED FRANCK–CONDON FACTORS BASED ON GLOBAL POTENTIAL ENERGY SURFACES

2005 ◽  
Vol 04 (01) ◽  
pp. 225-245 ◽  
Author(s):  
IKUO TOKUE ◽  
KATSUYOSHI YAMASAKI ◽  
SATOSHI MINAMINO ◽  
SHINKOH NANBU
Keyword(s):  
Potential Energy ◽  
Photoelectron Spectroscopy ◽  
Potential Energy Surfaces ◽  
Least Squares Method ◽  
Transition Probabilities ◽  
Three Dimensional ◽  
Equilibrium Geometry ◽  
Condon Factors ◽  
Energy Surfaces ◽  
Franck Condon

To elucidate the ionization dynamics, in particular the vibrational distribution, of H 2 O +(Ã) produced by photoionization and the Penning ionization of H 2 O and D 2 O with He *(2 3S) atoms, Franck–Condon factors (FCFs) were given for the [Formula: see text] ionization, and the transition probabilities were presented for the [Formula: see text] emission. The FCFs were obtained by quantum vibrational calculations using the three-dimensional potential energy surfaces (PESs) of [Formula: see text] and [Formula: see text] electronic states. The global PESs were determined by the multi-reference configuration interaction calculations with the Davidson correction and the interpolant moving least squares method combined with the Shepard interpolation. The obtained FCFs exhibit that the [Formula: see text] state primarily populates the vibrational ground state, as its equilibrium geometry is almost equal to that of [Formula: see text], while the bending mode (ν2) is strongly enhanced for the H 2 O +(Ã) state; the maximums in the population of H 2 O + and D 2 O + are approximately v2 = 11–12 and 15–17, respectively. These results are consistent with the distributions observed by photoelectron spectroscopy. Transition probabilities for the [Formula: see text] system of H 2 O + and D 2 O + show that the bending progressions consist primarily of the [Formula: see text] emission, with combination bands from the (1, v′2 = 4–8, 0) level being next most important.

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