Benchmarking Ground-State Geometries and Vertical Excitation Energies of a Selection of P-Type Semiconducting Molecules with Different Polarity

2015 ◽  
Vol 119 (51) ◽  
pp. 12876-12891 ◽  
Author(s):  
Charlotte Brückner ◽  
Bernd Engels
Keyword(s):  
Ground State ◽  
Excitation Energies ◽  
Vertical Excitation ◽  
P Type ◽  
Selection Of ◽  
Vertical Excitation Energies

Multireference configuration interaction studies of HCBr

2008 ◽  
Vol 86 (11) ◽  
pp. 1333-1343 ◽  
Author(s):  
S Burrill ◽  
F Grein
Keyword(s):  
Configuration Interaction ◽  
Ground State ◽  
Bond Angle ◽  
Rydberg States ◽  
Spectroscopic Constants ◽  
Excitation Energies ◽  
Transition Energies ◽  
Vertical Excitation ◽  
Upper Limits ◽  
Vertical Excitation Energies

Multireference configuration interaction (MRCI) potential curves were obtained for six 1A′, 1A′′, 3A′, and 3A′′ states of bromomethylene, HCBr, as functions of RCBr for bond angles of 102.9° and 130°, and as functions of the bond angle for RCBr = 1.8682 Å. Besides the well-known X1A′, a3A′′ and A1A′′ states, 21A′(3.26), 31A′(4.48), 41A′′(5.05), 41A′(5.06), 51A′(5.65), 43A′(6.00), 51A′′(6.60), 61A′′(6.60), 63A′′(6.61) (with estimated upper limits to the adiabatic transition energies in eV in parentheses), as well as several 5s and 6s Rydberg states, were found to be stable or metastable. Estimated spectroscopic constants for bound and metastable states, as well as vertical excitation energies for repulsive or quasi repulsive states are listed. The CH+Br dissociation energy of the ground state is about 3.5 eV, and 3.3 eV for a3A′′, whereas it is about 3.6 eV for CBr–H dissociation. It follows that photodissociation of ground-state HCBr by sunlight (up to 4.4 eV) can lead to both Br and H radicals. Photodissociation via several low-lying states is also possible. PACS Nos.: 31.10.+z, 31.15.Ar, 31.25.–v, 31.25.gf, 31.25.Qm, 31.50.Df, 31.15.Dj, 31.15.Fm

The structure and vertical excitation energies of the chlorothioformyl radical, ClCS: implications for the photofragmentation of thiophosgene

1993 ◽  
Vol 71 (1) ◽  
pp. 112-117 ◽  
Author(s):  
M. Hachey ◽  
F. Grein ◽  
R. P. Steer
Keyword(s):  
Energy Level ◽  
Ab Initio ◽  
Excited States ◽  
Ground State ◽  
Excited Electronic State ◽  
Excitation Energies ◽  
Electronically Excited States ◽  
Vertical Excitation ◽  
Electronically Excited ◽  
Vertical Excitation Energies

Ab initio CI studies have been performed to determine the geometry of the ground and first electronically excited states of the chlorothioformyl radical, ClCS, and the vertical excitation energies of its ten lowest doublet states and two lowest quartet states. The results are used to construct a more complete energy level correlation diagram for the photofragmentation of Cl2CS. The lowest excited electronic state of ClCS lies only 0.79 eV (adiabatic) above the ground state. Its discovery indicates that the results of previous photofragmentation experiments may need to be reinterpreted.

The ground state and low-lying excited states of CCCN radical and its ions: a CASSCF/CASPT2 study

2016 ◽  
Vol 94 (9) ◽  
pp. 803-807
Author(s):  
Angyang Yu
Keyword(s):  
Excited States ◽  
Ground State ◽  
Linear Structure ◽  
Electronic Configuration ◽  
Geometric Optimization ◽  
Oscillator Strengths ◽  
Basis Set ◽  
Excitation Energies ◽  
Complete Active Space ◽  
Vertical Excitation

The ground state and low-lying excited states of the CCCN radical and its ions have been investigated systematically using the complete active space self-consistent field (CASSCF) and multi-configuration second-order perturbation theory (CASPT2) methods in conjunction with the ANO-RCC-TZP basis set. The calculated results show that the state 12Σ+ has the lowest CASPT2 energy among the electronic states. By means of the geometric optimization of this radical, it could be found that the molecule exhibits linear structure, with the bond lengths R1 = 1.214 Å, R2 = 1.363 Å, R3 = 1.162 Å, which are very close to the experimental values. The calculated vertical excitation energies and the corresponding oscillator strengths show that there are three relatively strong peaks at energies 0.63, 4.04, and 5.49 eV, which correspond to the transitions 12Σ+ → 12Π, 12Σ+ → 22Π, and 12Σ+ → 22Σ+, respectively. Additionally, the electronic configuration and the harmonic vibration frequencies of each state are also investigated.

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