Role of Vibronic Coupling for the Dynamics of Intersystem Crossing in Eu3+ Complexes: an Avenue for Brighter Compounds

abstract

Understanding the dynamics of photophysical processes in Ln3+ complexes remains challenging due to the intricate nature involving the metallic center, where sensitization (antenna effect) plays a pivotal role. Current studies have often overlooked the vibronic coupling within the antenna effect, leading to incomplete insights into excited-state dynamics. To address these shortcomings, we introduce a novel theoretical and computational approach that leverages the impact of the vibrational modes of the S1 and T1 states in this effect through the correlation function formalism, offering a comprehensive view of intersystem crossing (ISC). Our approach achieves a desirable alignment between empirical and theoretical rates, outperforming previously employed semiclassical methods. A groundbreaking finding is that vibronic coupling with vibrations in the 700-1600 cm-1 energy range is crucial for higher ISC, and local vibrational mode analysis identified that this process is driven by delocalized vibrations across the molecule. These results shed light on the key molecular fragments responsible for vibronic coupling, opening an avenue for harnessing faster ISC by tailoring the ligand scaffold. Overall, it also demonstrates how ISC dynamics can serve as a bridge between theory and experiment, furnishing detailed mechanistic insights and a roadmap for the development of brighter compounds.

keywords

ANALYZING VIBRATIONAL-SPECTRA; ENERGY-TRANSFER; ELECTRON-TRANSFER; HERZBERG-TELLER; FRANCK-CONDON; SPIN-ORBIT; STATE; INTENSITIES; MOLECULES; TRANSITIONS

subject category

Chemistry; Physics

authors

Saraiva, LF; Neto, ANC; Bispo, AG Jr; Quintano, MM; Kraka, E; Carlos, LD; Lima, SAM; Pires, AM; Moura, RT Jr

Groups

G2 - Photonic, Electronic and Magnetic Materials

Projects

CICECO - Aveiro Institute of Materials (UIDB/50011/2020)

CICECO - Aveiro Institute of Materials (UIDP/50011/2020)

Associated Laboratory CICECO-Aveiro Institute of Materials (LA/P/0006/2020)

acknowledgements

The authors are thankful to all funding agencies that supported this research, FAPESP 2023/05718-9 and CNPq 308868/2022-6, 309448/2021-2, and the computations supplied by the Center of Scientific Computing (NCC/GridUnesp) no. 137 of Sao Paulo State University. This work was also partially developed within the scope of the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020 (DOI 10.54499/UIDB/50011/2020), UIDP/50011/2020 (DOI 10.54499/UIDP/50011/2020) & LA/P/0006/2020 (DOI 10.54499/LA/P/0006/2020), financed by Portuguese funds through the FCT/MCTES (PIDDAC). RTMJr thanks the Brazilian National Council for Scientific and Technological Development-CNPq, Grant numbers 406483/2023-0, 310988/2023-3, and 404742/2024-6. This work was financially supported by the National Science Foundation, grant CHE 2102461. MQ thanks SMU for the Postdoctoral Fellowship EK and MQ the Center for Research Computation at SMU for providing generous high-performance computational resources.