Communication: Unambiguous comparison of many-electron wavefunctions through their overlaps

Plasser, Felix; González, Leticia

doi:10.1063/1.4958462

Cited by 22 publications

(29 citation statements)

References 48 publications

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“…Figure 18 compactly shows the resulting energies of the excited states on the vertical axis, with colored horizontal bars indicating the state character. The di erent TD-DFT results are correlated (gray lines) using overlap calculations [74,194].…”

Section: In Uence Of the Method: Exchange-and Correlation E Ects In [mentioning

confidence: 99%

“…With the goal to ameliorate this situation, an automatic procedure to analyze wave functions as well as electron densities has been recently designed, providing a variety of visual and quantitative exploration methods for excitedstate computations [70][71][72][73][74]. This comprehensive toolbox has shown to be useful whenever a large number of excited states is to be analyzed, e.g., ensemble calculations of spectra, trajectory simulations, or higher excited states [75][76][77][78].…”

Section: Introductionmentioning

confidence: 99%

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Quantitative wave function analysis for excited states of transition metal complexes

Mai

Dorn

Fumanal

et al. 2018

Coordination Chemistry Reviews

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134

163

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The character of an electronically excited state is one of the most important descriptors employed to discuss the photophysics and photochemistry of transition metal complexes. In transition metal complexes, the interaction between the metal and the di erent ligands gives rise to a rich variety of excited states, including metal-centered, intra-ligand, metal-to-ligand charge transfer, ligand-to-metal charge transfer, and ligand-to-ligand charge transfer states. Most often, these excited states are identi ed by considering the most important wave function excitation coe cients and inspecting visually the involved orbitals. This procedure is tedious, subjective, and imprecise. Instead, automatic and quantitative techniques for excited-state characterization are desirable. In this contribution we review the concept of charge transfer numbers-as implemented in the TheoDORE package-and show its wide applicability to characterize the excited states of transition metal complexes. Charge transfer numbers are a formal way to analyze an excited state in terms of electron transitions between groups of atoms based only on the well-de ned transition density matrix. Its advantages are many: it can be fully automatized for many excited states, is objective and reproducible, and provides quantitative data useful for the discussion of trends or patterns. We also introduce a formalism for spin-orbit-mixed states and a method for statistical analysis of charge transfer numbers. The potential of this technique is demonstrated for a number of prototypical transition metal complexes containing Ir, Ru, and Re. Topics discussed include orbital delocalization between metal and carbonyl ligands, nonradiative decay through metal-centered states, e ect of spin-orbit couplings on state character, and comparison among results obtained from di erent electronic structure methods.

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Section: In Uence Of the Method: Exchange-and Correlation E Ects In [mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Quantitative wave function analysis for excited states of transition metal complexes

Mai

Dorn

Fumanal

et al. 2018

Coordination Chemistry Reviews

Self Cite

134

163

View full text Add to dashboard Cite

show abstract

“…The character of the involved states, shown in Figures 6c, was analyzed by calculating wave function overlaps to the states at the equilibrium geometry; these overlaps allow to compare states for hundreds of calculations without individually inspecting the orbital and expansion coefficients. 57 This analysis showed that for the large majority of sampled geometries (Figure 6c), S 1 has ππ * character and S 2 has n O π * character, whereas for the higher states the character varies with geometry, e.g., the πσ * state which is distributed between the S 2 -S 5 . Comparing the spectrum to experimental spectra, we find that the MS-CASPT2 calculations qualitatively reproduce the first absorption band of 5BU, but the sampling has shifted the peak to slightly lower energies than those predicted experimentally.…”

Section: Absorption Spectrummentioning

confidence: 93%

Insights into the deactivation of 5-bromouracil after ultraviolet excitation

Peccati

Mai

González

2017

Phil. Trans. R. Soc. A.

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5-Bromouracil is a nucleobase analogue that can replace thymine in DNA strands and acts as a strong radiosensitizer, with potential applications in molecular biology and cancer therapy. Here, the deactivation of 5-bromouracil after ultraviolet irradiation is investigated in the singlet and triplet manifold by accurate quantum chemistry calculations and non-adiabatic dynamics simulations. It is found that, after irradiation to the bright* state, three main relaxation pathways are, in principle, possible: relaxation back to the ground state, intersystem crossing (ISC) and C-Br photodissociation. Based on accurate MS-CASPT2 optimizations, we propose that ground-state relaxation should be the predominant deactivation pathway in the gas phase. We then employ different electronic structure methods to assess their suitability to carry out excited-state dynamics simulations. MRCIS (multi-reference configuration interaction including single excitations) was used in surface hopping simulations to compute the ultrafast ISC dynamics, which mostly involves the * and* states.This article is part of the themed issue 'Theoretical and computational studies of non-equilibrium and non-statistical dynamics in the gas phase, in the condensed phase and at interfaces'.

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“…Computing the overlap between full electronic wave functions is a common practice to compare ESs at the same or different molecular geometries. [38][39][40]45] On the other hand, the nature of the ESs can also be described by inspecting only the nature of the "hole" and the "particle" entities. Indeed, computing the mono-electronic wave function overlap between NTOs has proven to be a robust procedure to compare ESs.…”

Section: Theoretical Backgroundmentioning

confidence: 99%

“…On the other hand, a vast amount of mono-electronic orbital overlaps is required to fully compute the many-electron wave function overlap. [38,39] Needless to say, this new formalism represents a remarkable advantage with respect to standard CI-based methods in terms of computational efficiency. Following our same line of thought, Sapunar and co-workers have very recently proven the superior computational efficiency of NTO-over CI-based algorithms for the computation of ESs wave function overlaps.…”

Section: Introductionmentioning

confidence: 99%

Following the evolution of excited states along photochemical reaction pathways

Campetella

Garcı́a

2020

J Comput Chem

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Analyzing the behavior of potential energy surfaces (PESs) of diabatic excited states (ESs) becomes of crucial importance for a complete understanding of complex photochemical reactions. Since the definition of a compact representation for the transition density matrix, the use of the natural transition orbitals (NTOs) has become a routine practice in time‐dependent density functional theory calculations. Their popularity has remarkably grown due to its simple orbital description of electronic excitations. Indeed, very recently, we have presented a new formalism used for the optimization of ESs by tracking the state of interest computing the NTO's overlap between consecutive steps of the procedure. In this new contribution, we generalize the use of this NTO's overlap‐based state‐tracking formalism for the analysis of all the desired diabatic states along any chemical reaction pathway. Determining the PES of the different diabatic states has been automatized by developing an extension of our recently presented algorithm, the so‐called SDNTO: “Steepest Descent minimization using NTOs.” This automatized overlap‐based procedure allows an agile and convenient analysis of the evolution of the ESs avoiding the intrinsic ambiguity of visualizing orbitals or comparing physical observables. The analysis of two photochemical reactions of the same nature with different PES landscapes perfectly illustrates the utility of this new tool.

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Communication: Unambiguous comparison of many-electron wavefunctions through their overlaps

Cited by 22 publications

References 48 publications

Quantitative wave function analysis for excited states of transition metal complexes

Quantitative wave function analysis for excited states of transition metal complexes

Insights into the deactivation of 5-bromouracil after ultraviolet excitation

Following the evolution of excited states along photochemical reaction pathways

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