On the Electronic States of S4+ and S4- Isomers

2007 ◽  
Vol 72 (1) ◽  
pp. 83-99 ◽  
Author(s):  
Hanka Sormova ◽  
Roberto Linguerri ◽  
Pavel Rosmus ◽  
Jürgen Fabian ◽  
Najia Komiha
Keyword(s):  
Electronic Transition ◽  
Electronic States ◽  
Theoretical Data ◽  
Electron Affinities ◽  
Excitation Energies ◽  
Ionization Energies ◽  
Transition Moments ◽  
Higher Spin ◽  
Large Amplitude Vibrations ◽  
Equilibrium Geometries

For three energetically most stable structures of tetrasulfur, S4, S4+ and S4- (cis-chain, rectangular, and trans-chain forms), equilibrium geometries, harmonic wavenumbers, ionization energies, electron affinities, electronic vertical and adiabatic excitation energies, and electronic transition moments were calculated by ab initio methods. It was found that similarly to the ground state of S4, the S4+ cis-isomer could interconvert, perturbed, however, by vibronic coupling with a very close-lying excited state and large-amplitude vibrations. Moreover, the cis- and rectangular minima are calculated to be energetically degenerated. The ω values in all three species agree reasonably well with existing experimental and theoretical data. The calculated patterns of harmonic modes suggest the existence of very complex low-lying anharmonic polyads in all three species. The calculated ionization energies reported previously are compared with the present more accurate data. Also the electronic transition moments and the energy positions of the electronic states with higher spin multiplicities are given.

GEOMETRIES AND ENERGY SEPARATIONS OF ELECTRONIC STATES OF In3N, InN3, AND THEIR IONS

2008 ◽  
Vol 07 (04) ◽  
pp. 751-765 ◽  
Author(s):  
ZHIJI CAO ◽  
KRISHNAN BALASUBRAMANIAN
Keyword(s):  
Ground State ◽  
Electronic States ◽  
Closed Shell ◽  
Spectroscopic Properties ◽  
Electron Affinities ◽  
Complete Active Space ◽  
Consistent Field ◽  
Self Consistent ◽  
Self Consistent Field ◽  
Equilibrium Geometries

Spectroscopic properties of the low-lying electronic states of In 3 N , InN 3, and their ions are computed by the complete active-space self-consistent field (CASSCF) followed by multireference singles + doubles configuration interaction (MRSDCI) calculations. Our results predict that the spectra of In 3 N / InN 3 are substantially different from those of Ga 3 As / GaAs 3 and Al 3 P / AlP 3 tetramers. The ground state of In 3 N is a closed-shell 1 A ′1 state with a planar D 3h symmetry, whereas the ground state of InN 3 is a 1Σ+ state of linear In – N – N – N structure. The equilibrium geometries, vibrational frequencies, atomization energies, adiabatic ionization potentials, electron affinities, and other properties are discussed.

scholarly journals Benchmarking semiempirical, Hartree–Fock, DFT, and MP2 methods against the ionization energies and electron affinities of short- through long-chain [n]acenes and [n]phenacenes

2016 ◽  
Vol 94 (3) ◽  
pp. 251-258 ◽  
Author(s):  
Sierra Rayne ◽  
Kaya Forest
Keyword(s):  
Density Functional ◽  
Theoretical Data ◽  
Theory Model ◽  
Basis Set ◽  
Electron Affinities ◽  
Ionization Energies ◽  
Hartree Fock ◽  
Wide Range ◽  
High Level ◽  
Long Chain

Vertical and adiabatic ionization energies (IEs) and electron affinities (EAs) were calculated for the n = 1–10 [n]acenes using a wide range of semiempirical, Hartree–Fock, density functional, and second-order Moller–Plesset perturbation theory model chemistries. None of the model chemistries examined was able to accurately predict the IEs or EAs for both short- through long-chain [n]acenes, as well as for extrapolations to the polymeric limit, when compared to available experimental and benchmark theoretical data. Except for 6-31G(d), the choice of the basis set does not affect B3LYP results significantly. Analogous calculations using a suite of eight modern and (or) popular density functionals for the n = 1–10 [n]phenacenes revealed similar problems in estimating the IEs and EAs of these compounds, with the sole exception of the M062X functional for adiabatic IEs and potentially the APFD, B3LYP, and MN12SX functionals for adiabatic EAs. The poor IE/EA prediction performance for the parent [n]acenes and [n]phenacenes may extend to their substituted derivatives and heteroatom-substituted analogs. Consequently, caution should be exercised in the application of non-high-level calculations for estimating the IE/EA of these important classes of materials.

ANOMALOUS ROTATIONAL LINE INTENSITIES IN ELECTRONIC TRANSITIONS OF POLYATOMIC MOLECULES: AXIS-SWITCHING

1965 ◽  
Vol 43 (2) ◽  
pp. 298-320 ◽  
Author(s):  
J. T. Hougen ◽  
J. K. G. Watson
Keyword(s):  
Electronic State ◽  
Electronic Transition ◽  
Electronic States ◽  
Polyatomic Molecules ◽  
Electronic Transitions ◽  
Rotational Line ◽  
Line Intensities ◽  
Fixed Axis ◽  
Axis Switching ◽  
Equilibrium Geometries

It is convenient when performing calculations on a vibrating and rotating molecule to define an axis system which is somehow fixed to the molecule. The orientation of the usual molecule-fixed axis system, however, depends not only upon the instantaneous positions of the nuclei, but also upon the equilibrium positions from which the nuclei are regarded as being displaced. Thus, when a molecule of low enough symmetry undergoes an electronic transition accompanied by a change in geometry, it will, in general, be necessary to consider two molecule-fixed axis systems, corresponding to the two different electronic states. This change in axis system from one electronic state to another will be called axis-switching. The two axis systems can be related to each other by the 3 × 3 rotation matrix which brings them into coincidence. The elements of this matrix are functions of the equilibrium geometries of the two electronic states as well as of the instantaneous positions of the atoms in the molecule. Axis-switching leads to departures from the usual expressions for the intensities of rotational lines, the effects of which are most noticeable in near-symmetric tops. The forbidden subbands occurring in the 2 400 Å system of acetylene can be satisfactorily explained by axis-switching. Axis-switching effects may also be present in the spectra of HCN, HSiCl, and HSiBr.

THE STUDY OF THE PROPERTIES OF THE GROUND- AND LOW-LYING EXCITED STATES OF ASH2, ${\rm ASH}_{2}^{+}$ AND ${\rm ASH}_{2}^{-}$

2013 ◽  
Vol 12 (02) ◽  
pp. 1250115 ◽  
Author(s):  
YANLI HUO ◽  
MEISHAN WANG ◽  
CHUANLU YANG ◽  
HONGFEI WANG ◽  
ZIXIA MA
Keyword(s):  
Excited States ◽  
Dipole Moments ◽  
Electronic States ◽  
Theoretical Data ◽  
Ionization Potentials ◽  
Basis Sets ◽  
Excitation Energies ◽  
Transition Dipole ◽  
Vertical Excitation ◽  
Cluster Configuration

The properties of the ground and excited states of AsH2 , [Formula: see text] and [Formula: see text] have been investigated by using symmetry-adapted-cluster (SAC)/symmetry-adapted-cluster configuration interaction (SAC-CI) method. The geometry of the ground state of AsH2 is optimized at SAC method with different basis sets. The calculated results with cc-pVTZ and cc-pVQZ basis sets are in very good agreement with the experimental and previous theoretical data. The geometry and the properties of eight low-lying electronic excited states of AsH2 are obtained at SAC-CI/cc-pVTZ and SAC-CI/cc-pVQZ level, including geometries, vertical excitation energies, adiabatic excitation energies, transition dipole moments, and oscillation strengths. Employing the same theoretical level as AsH2 , the geometries, adiabatic ionization potentials (AIPs), and vertical ionization potentials (VIPs) of the ground and eight low-lying electronic states of [Formula: see text] are investigated as well as the geometries, vertical detachment energies (VDEs) and adiabatic detachment energies (ADEs) of nine electronic states of [Formula: see text]. Comparing with the available experimental or previous theoretical data, the SAC/SAC-CI/cc-pVTZ and SAC/SAC-CI/cc-pVQZ results are reliable for AsH2 , [Formula: see text] and [Formula: see text]. The predicted results can afford the useful information for one to deeply investigate them from the spectral experiment.

AsCl radical: The low-lying electronic states and the (1) 3 Π → X 3 Σ − electronic transition

2015 ◽  
Vol 634 ◽  
pp. 66-70 ◽  
Author(s):  
Marcelo A.P. Pontes ◽  
Marcos H. de Oliveira ◽  
Luiz F.A. Ferrão ◽  
Orlando Roberto-Neto ◽  
Joaquim D. Da Motta Neto ◽  
...  
Keyword(s):  
Electronic Transition ◽  
Electronic States
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