Development of a Novel Index for Analysis of Electronically Excited States

Abstract

Concerning the major factors in the context of excited states analyses, namely charge centroids of the orbitals involved in the excitations, the distance between orbital centroids, and overlap integrals, a new metric-the Ω index-is proposed to assign the character and optical properties of electronically excited states. Using several molecules from different classes and also a well-studied standard database for time-dependent density functional theory (TD-DFT) studies as benchmark criteria, accountability of the developed index is numerically assessed for local, charge transfer, and Rydberg excitations. It is shown that the nature of excited states can be discriminated using the Ω index, where its superior performance for those situations in which the previous descriptors were not helpful is also unveiled. Relationships are also examined between the Ω index and optical properties of some molecules under study in the framework of the sum-over-state approach. It is observed that there are correlations between the proposed index and computed hyperpolarizabilities based on the sum-over-state scheme. These findings offer the possibility of estimating excited-state properties of large systems from simple descriptors without explicitly performing calculations of high-order response functions.

N‐doped cycloparaphenylenes: Tuning electronic properties for applications in thermally activated delayed fluorescence

“…This reduction is related (vide infra) to the spatial separation, and thus poor overlap, of the HOMO and LUMO corresponding orbitals, as it was qualitatively evidenced in Figure . However, for compound 9 , which registers a larger overlap between these orbitals (see also Figure ) the value increases again showing the marked relationship between these two quantities in agreement with other recent studies …”

Photophysics of OLED Materials with Emitters Exhibiting Thermally Activated Delayed Fluorescence and Used in Hole/Electron Transporting Layer from Optimally Tuned Range-Separated Density Functional Theory

“…This is more pronounced especially for the compounds with large charge-transfer character and very small singlet−triplet gaps where the first singlet and triplet excited states are locally parallel. For instance, for some molecules with an envisioned large charge-transfer character based on our recently proposed excited states index and hole− electron distributions, 105 such as PPZ-DPO and PXZ-TRZ, it also been recognized that they have also small singlet−triplet energy gaps. 20 The theoretically predicted values of the singlet−triplet energy gaps obtained from the OT-RSHs based on BLYP and PBE approximations with α = 0.0, β = 1.0 combination along with optimally tuned values of rangeseparation parameter are, respectively, 0.09 and 0.09 eV (PPZ-DPO) and 0.07 and 0.06 eV (PXZ-TRZ), in close agreement with the experimental singlet−triplet energy gaps of 0.09 and 0.06 eV for the two molecules, respectively.…”

Theoretical study of the electric and the magnetic dipole in UV-Vis and ECD of fluralaner: the folded conformation and the extended conformation

“…In this field, a considerable attention has been drawn in the literature [4][5][6][7][8][9][10][11]. The Time Dependent Density Functional Theory (TDDFT) is a really successful theory of electronic structure of matter, where the TDDFT has drawn a considerable attention in the literature [7,[11][12][13][14][15][16][17][18][19][20][21][22][23][24] for calculating the transitions energy with relative intensity. According to this computation, many of objects are resulting such as: the difference in density matrix, which is known as the difference between the excited and ground states density matrix expressed on the basis set of atomic functions.…”