Magnetic and spectroscopic properties of Os2(O2CR)4Cl2. Evidence for a 3(δ*π*) ground state

2008 ◽  
pp. 41-57
Author(s):  
Vincent M. Miskowski ◽  
Harry B. Gray
Keyword(s):  
Ground State ◽  
Spectroscopic Properties

Potential curves and spectroscopic properties for the ground state of ClO and for the ground and various excited states of ClO−

2002 ◽  
Vol 117 (21) ◽  
pp. 9703-9709 ◽  
Author(s):  
Seung-Joon Kim ◽  
Young-Joo Kim ◽  
Chang-Ho Shin ◽  
Byung-Jin Mhin ◽  
T. Daniel Crawford
Keyword(s):  
Excited States ◽  
Ground State ◽  
Spectroscopic Properties ◽  
Potential Curves

Cluster expansion of the wavefunction. Potential energy curves of the ground, excited, and ionized states of Li2

1985 ◽  
Vol 63 (7) ◽  
pp. 1857-1863 ◽  
Author(s):  
H. Nakatsuji ◽  
J. Ushio ◽  
T. Yonezawa
Keyword(s):  
Experimental Data ◽  
Potential Energy ◽  
Cluster Expansion ◽  
Ground State ◽  
Spectroscopic Properties ◽  
Bound State ◽  
Potential Energy Curves ◽  
Interaction Theory ◽  
Theoretical Results ◽  
S States

The SAC (symmetry-adapted-cluster) and SAC-CI theories based on the cluster expansion of the wavefunction have been applied to the calculations of the potential energy curves of the ground, excited, and ionized states of the Li2 molecule. The potential energy curves and the spectroscopic properties calculated agree well with the available experimental data and the previous theoretical results of Olson and Konowalow. For the [Formula: see text] state, our calculation is the first and predicts a bound state whose minimum is at Re = 6.8 bohr and 2.5 eV above the ground state. This state dissociates into 2P and 2S states of the Li atoms and has a hump which is higher than and outside of the hump of the B1IIu state. The long-range behavior of the states which dissociate into 2P and 2S states of the Li atom is well predicted by the resonance interaction theory.

Effect of Ligands on the Photoluminescence Performance of Ir(III) Complexes: A Theoretical Exploration

2013 ◽  
Vol 798-799 ◽  
pp. 219-222
Author(s):  
Jian Po Zhang ◽  
Li Jin ◽  
Xing Jin ◽  
Xiu Yun Sun ◽  
Fu Quan Bai
Keyword(s):  
Charge Transfer ◽  
Ground State ◽  
Electronic Structures ◽  
Spectroscopic Properties ◽  
Molecular Orbitals ◽  
Experimental Results ◽  
Frontier Molecular Orbitals ◽  
Bond Lengths ◽  
Td Dft

A series of iridium (III) complexes (C^N)2Ir (Pic) (C^N = Phi (1), Ppi (2), Mpfpi (3), and Cpfpi (4) have been investigated theoretically to explore their electronic structures and spectroscopic properties. The calculate bond lengths of Ir-N and Ir-O in the ground state agree well with the corresponding experimental results. At the TD-DFT and PCM levels, 1-4 give rise to absorptions at 359, 360, 348, and 335 nm and phosphorescent emissions at 454 , 469, 441, and 425 nm, respectively. The transitions of 1-4 are all attributed to {[d (Ir)+π (C^N)][π*(C^N) or π*(Pic)]} charge transfer. It is shown that the emissions are significantly dominated by the metal participating in the frontier molecular orbitals and affected by the C^N ligands.

Electronic structure of low-spin six-coordinate iron(III) meso-tetrapropylchlorin complexes

2014 ◽  
Vol 18 (08n09) ◽  
pp. 778-791 ◽  
Author(s):  
Akira Ikezaki ◽  
Jyunpei Ono ◽  
Yoshiki Ohgo ◽  
Mari Fukagawa ◽  
Takahisa Ikeue ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Ground State ◽  
Nmr Spectra ◽  
Spectroscopic Properties ◽  
H Nmr ◽  
Axial Ligands ◽  
Splitting Parameter ◽  
Nmr Signals ◽  
Electronic Ground ◽  
C Nmr

Low-spin iron(III) tetrapropylchlorins [ Fe ( T n PrC ) L 2]± (L = HIm, 1-MeIm, DMAP, CN-, 4-CNPy, tBuNC) adopt the dxy-type ground state regardless of the nature of axial ligands. Among the complexes examined, [ Fe ( T n PrC )( t BuNC )2]+ has shown quite unique spectroscopic properties as described below. (1) 1 H NMR signals were extremely broad as compared with those of other complexes. In particular, 5,20- CH 2(α) signal was too broad to detect. (2) No signals except C γ were observed in 13 C NMR spectra. (3) Tetragonal splitting parameter (|Δ|) estimated by the EPR g values at 4.2 K reached as much as 12.4 λ, which is the largest |Δ| value among all the low-spin iron(III) porphyrins and porphyrinoids reported previously. On the basis of these results, we have concluded that [ Fe ( T n PrC )( t BuNC )2]+ adopts the low-spin iron(III) with (dxz, dyz)4(dxy)1 electronic ground state at 4.2–30 K where the EPR spectra are taken, while it should be expressed as the low-spin Fe ( II ) chlorin π-radical cation [ Fe II ( T n PrC .)( t BuNC )2]+ at ambient temperature where the NMR spectra are taken.

Density Functional Study of the Electronic Structure and Related Properties of Pt(NO)/Pt(NO2) Redox Couples

2003 ◽  
Vol 68 (3) ◽  
pp. 423-446 ◽  
Author(s):  
Paraskevas Karipidis ◽  
Athanassios C. Tsipis ◽  
Constantinos A. Tsipis
Keyword(s):  
Ground State ◽  
Density Functional ◽  
Activation Barrier ◽  
Spectroscopic Properties ◽  
Redox Couple ◽  
Basis Set ◽  
Stationary Points ◽  
Functional Study ◽  
Dft Theory ◽  
Exothermic Process

Density functional calculations at the B3LYP level of theory, using the SDD basis set, provide satisfactory description of geometric, energetic, electronic and spectroscopic properties of the Pt(NO)/Pt(NO2) redox couple. The neutral Pt(NO) species adopts a bent 2A' ground state, while the cationic [Pt(NO)]+ species adopts a linear 1Σ+ ground state. The B3LYP/SDD- predicted Pt-N bond lengths are 2.016 and 1.777 Å for Pt(NO) (2A') and [Pt(NO)]+ (1Σ+), respectively, while the ∠Pt-N-O bent angle for [Pt(NO)] (2A') is 119.6°. On the other hand, the anionic [Pt(NO)]- species adopts the bent 1A' ground state with a Pt-N bond length of 1.867 Å and a ∠Pt-N-O bent angle of 122.5°. The computed binding energies of the NO, NO+ and NO- ligands with Pt(0) were found to be 29.9 (32.8), 69.9 (78.4) and 127.4 (128.7) kcal/mol at the B3LYP/SDD and CCSD(T)/SDD (numbers in parentheses) levels of theory, respectively. Moreover, the structure of the [Pt(NO2)]+ component of the Pt(NO)/Pt(NO2) redox couple and its transformation to [Pt(NO)]+ upon reaction with CO was analysed in the framework of the DFT theory. The coordination of the CO ligand to [Pt(NO2)]+ affords the cationic mixed-ligand [Pt(CO)(NO2)]+ complex, which is stabilized by 66.6 (60.5) kcal/mol, with respect to the separated [Pt(NO2)]+ and CO in their ground states. The O-transfer reaction from the coordinated NO2 to the coordinated CO ligands in the presence of the [Pt(NO2)]+ species corresponds to an exothermic process; the heat of the reaction (∆RH) is -85.2 (-80.5) kcal/mol and the activation barrier amounts to 27.7 (33.0) kcal/mol. Finally, the equilibrium structures of selected stationary points related to the transformation of NO to NO2 ligand located on the potential energy surfaces of the [Pt(NO),O2], [Pt(NO)+,O2], and [Pt(NO)-,O2] systems were analysed in the framework of the DFT theory. The computed interaction energies of O2 with Pt(NO), [Pt(NO)]+ and [Pt(NO)]- species were found to be 106.9 (105.3), 49.2 (48.4) and 26.9 (26.5) kcal/mol, respectively. The O2 ligand is coordinated to the Pt central atom in an end-on mode for [Pt(NO),O2] and [Pt(NO)-,O2] systems and in a side-on mode for the [Pt(NO)+,O2] system. The transformation of NO to NO2 in [Pt(NO)]- species upon reaction with dioxygen corresponds to an exothermic process; the heat of the reaction (∆RH) is -60.6 (-55.8) kcal/mol, while the activation barrier amounts to 35.5 (30.2) kcal/mol. Calculated structures, relative stability and bonding properties of all stationary points are discussed with respect to computed electronic and spectroscopic properties, such as charge density distribution and harmonic vibrational frequencies.

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.

Quantum chemical B3LYP/cc-pvqz computation of ground-state structures and properties of small molecules with atoms of Z ≤ 18 (hydrogen to argon)(IUPAC Technical Report)

2001 ◽  
Vol 73 (9) ◽  
pp. 1521-1553 ◽  
Author(s):  
Rudolf Janoschek
Keyword(s):  
Small Molecules ◽  
Ground State ◽  
Quantum Chemical ◽  
Density Functional ◽  
Spectroscopic Properties ◽  
Computational Method ◽  
Coupling Constants ◽  
Basis Sets ◽  
General Question ◽  
Absolute Deviation

Since density functional theory (DFT) achieved a remarkable break-through in computational chemistry, the important general question "How reliable are quantum chemical calculations for spectroscopic properties?" should be answered anew. In this project, the most successful density functionals, namely the Becke B3LYP functionals, and the correlation-consistent polarized valence quadruple zeta basis sets (cc-pvqz) are applied to small molecules. In particular, the complete set of experimentally known diatomic molecules formed by the atoms H to Ar (these are 214 species) is uniformly calculated, and calculated spectroscopic properties are compared with experimental ones. Computationally demanding molecules, such as open-shell systems, anions, or noble gas compounds, are included in this study. Investigated spectroscopic properties are spectroscopic ground state, equilibrium internuclear distance, harmonic vibrational wavenumber, anharmonicity, vibrational absolute absorption intensity, electric dipole moment, ionization potential, and dissociation energy. The same computational method has also been applied to the ground-state geometries of 56 polyatomic molecules up to the size of benzene. Special sections are dedicated to nuclear magnetic resonance (NMR) chemical shifts and isotropic hyperfine coupling constants. Each set of systems for a chosen property is statistically analyzed, and the above important question "How reliable...?" is mathematically answered by the mean absolute deviation between calculated and experimental data, as well as by the worst agreement. In addition to presentation of numerous quantum chemically calculated spectroscopic properties, a corresponding updated list of references for experimentally determined properties is presented.

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