DFT study of electron absorption and emission spectra of pyramidal LnPc(OAc) complexes of some lanthanide ions in the solid state

Hanuza, J.; Godlewska, P.; Lisiecki, Radosław; Ryba‐Romanowski, W.; Kadłubański, Paweł; Lorenc, J.; Łukowiak, Anna; Macalik, L.; Gerasymchuk, Yuriy; Legendziewicz, J.

doi:10.1016/j.saa.2018.01.003

Cited by 11 publications

(6 citation statements)

References 51 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The complexes were energetically optimized by Becke 3-parameter exchange and Lee−Yang− Parr correlation functionals with the Coulomb-attenuating method (CAM-B3LYP). 35 Time-dependent DFT calculations for [SmCl 6 ] 4− were performed to obtain a simulated UV−vis spectrum with the same basis sets and functionals. 36−39 To consider the effect of the surrounding LiCl-KCl melt, a polar continuum solvation model was adopted with a dielectric constant (ε) of 2.3741, because it is known that the dielectric constant of ionic liquids ranges from 2 to 3.…”

Section: Computational Detailsmentioning

confidence: 99%

Electrochemical Formation of Divalent Samarium Cation and Its Characteristics in LiCl–KCl Melt

et al. 2018

View full text Add to dashboard Cite

The electrochemical reduction of trivalent samarium in a LiCl-KCl eutectic melt produced highly stable divalent samarium, whose electrochemical properties and electronic structure in the molten salt were investigated using cyclic voltammetry, UV-vis absorption spectroscopy, laser-induced emission spectroscopy, and density functional theory (DFT) calculations. Diffusion coefficients of Sm and Sm were electrochemically measured to be 0.92 × 10 and 1.10 × 10 cm/s, respectively, and the standard apparent potential of the Sm couple was estimated to be -0.82 V vs Ag|Ag at 450 °C. The spectroelectrochemical study demonstrated that the redox behavior of the samarium cations obeys the Nernst equation ( E°' = -0.83 V, n = 1) and the trivalent samarium cation was successfully converted to the divalent cation having characteristic absorption bands at 380 and 530 nm with molar absorptivity values of 1470 and 810 M cm, respectively. Density function theory calculations for the divalent samarium complex revealed that the absorption signals originated from the 4f to 4f5d transitions. Additionally, laser-induced emission measurements for the Sm cations in the LiCl-KCl matrix showed that the Sm ion in the LiCl-KCl melt at 450 °C emitted an orange color of fluorescence, whereas a red colored emission was observed from the Sm ion in the solidified LCl-KCl salt at room temperature.

show abstract

Section: Computational Detailsmentioning

confidence: 99%

Electrochemical Formation of Divalent Samarium Cation and Its Characteristics in LiCl–KCl Melt

et al. 2018

View full text Add to dashboard Cite

show abstract

“…Calculations employing relativistically recontracted Karlsruhe (Douglas–Kroll–Hess – DKH or zero-order regular approximation for relativistic effects – ZORA) basis sets , with segmented all-electron relativistically contracted basis sets or atomic natural orbital basis sets are often impracticable for sets of lanthanide complexes because of the immense time required. Hence, many time dependent–density functional theory (TD-DFT) calculations − have been attempted on lanthanide ion complexes using effective core potentials (ECPs), which place the electronic ground state as a 4f N configuration (for example, a high spin septet for Eu 3+ using the Stuttgart group ECP 28MWB , or as a closed shell: 52MWB for Eu 3+ ) . In the latter case, the intra-4f N energy levels of Eu 3+ are not considered and only the relevant ligand levels in the complex are calculated.…”

Section: Introductionmentioning

confidence: 99%

Determination of Triplet State Energy and the Absorption Spectrum for a Lanthanide Complex

et al. 2021

View full text Add to dashboard Cite

The usual depiction of energy transfer from an antenna of a lanthanide complex, LnL n , to the lanthanide ion, Ln3+, such as Eu3+ or Tb3+, is illustrated by an energy diagram matching the complex and metal ion levels. Other than direct singlet energy transfer (ET), relaxation to the lowest triplet state, T1, may be followed by ET. The determination of the zero phonon line triplet state energy, T1, is thus essential for the rationalization of the ET processes of lanthanide ions. It is also useful to calculate the electronic absorption spectra of lanthanide complexes to pinpoint maximum absorption. The triplet state energy and the energies of absorption bands have not been thoroughly investigated by calculation and compared with experimental results in a critical manner previously. In order to study and provide guidelines on these points, we have made an experimental and theoretical investigation of the energy levels of lanthanide complexes in the solid state and in solution by employing well-characterized compounds. It is found that time dependent–density functional theory (TD-DFT) methods do not provide a good indication of the complex absorption spectrum, but reasonable agreement is achieved from multireference methods or more rapidly from the Zerner’s intermediate neglect of differential overlap (ZINDO/S) semiempirical method for calculating excited states. Although the absorption spectra of the complexes may be similar for different lanthanide ions and may be fairly similar to those of the ligands, the use of a fragment scheme to calculate absorption spectra using TD-DFT is generally not accurate. The major absorption bands correspond to higher energy singlet transitions and the energies of the first singlet and triplet states are not well-predicted by the above methods. The calculation of the triplet zero phonon line energy is best performed by the correction of the adiabatic transition energy by the difference in the zero-point vibrational energy of the ground singlet (S0) and the triplet (T1) states: the ΔSCF (self-consistent field) method. The geometry optimization of the complex in each electronic state followed by confirmatory vibrational frequency calculations is thus required. This study lays down the platform for a more accurate description and understanding of the ET processes of lanthanide ions in organic complexes.

show abstract

“…The electronic properties were calculated according to Koopmans theorem [11,12]. Excitation energies and electronic transitions are carried out by using the Time Dependent TD density functional theory [12][13][14].…”

Section: Computation Methodsmentioning

confidence: 99%

Electronic Structure, IR and UV-Vis Spectra of Some Suggested Ziegler-Natta Catalysts

AL-Temimei¹,

Abbood²

2018

JK-Physics

View full text Add to dashboard Cite

Three aluminum metal complexes were suggested as Ziegler-Natta catalysts and studied theoretically at the ground and excited states. Becke's three parameter exchange with Lee, Yang, and Parr correlation functional) density functional theory and SDD (Stuttgart Dresden triple zeta ECPs (Effective-Core Potential))basis sets calculations were employed to study the electronic structure and IR-spectra of the complexes. Time dependent of DFT method is used to calculate the excitation energies and electronic transitions for each complex. The results of density of state(DOS) and the distribution of HOMO and LUMO showed these complexes are good suggestion to play role for polymerization processes as catalysts.Theresults showed that the excitation energies lie in the UV-Vis region.http://dx

show abstract

DFT study of electron absorption and emission spectra of pyramidal LnPc(OAc) complexes of some lanthanide ions in the solid state

Cited by 11 publications

References 51 publications

Electrochemical Formation of Divalent Samarium Cation and Its Characteristics in LiCl–KCl Melt

Electrochemical Formation of Divalent Samarium Cation and Its Characteristics in LiCl–KCl Melt

Determination of Triplet State Energy and the Absorption Spectrum for a Lanthanide Complex

Electronic Structure, IR and UV-Vis Spectra of Some Suggested Ziegler-Natta Catalysts

Contact Info

Product

Resources

About