Evaluating the anharmonicity contributions to the molecular excited state internal conversion rates with finite temperature TD-DMRG

2021 ◽  
Vol 154 (21) ◽  
pp. 214109
Author(s):  
Yuanheng Wang ◽  
Jiajun Ren ◽  
Zhigang Shuai
Keyword(s):  
Excited State ◽  
Finite Temperature ◽  
Internal Conversion ◽  
Conversion Rates ◽  
Molecular Excited State

scholarly journals Evaluating the Anharmonicity Contributions to the Molecular Excited State Internal Conversion Rates with Finite Temperature TD-DMRG

2021 ◽  
Author(s):  
Yuanheng Wang ◽  
Jiajun Ren ◽  
Zhigang Shuai
Keyword(s):  
Excited State ◽  
Excitation Energy ◽  
Internal Conversion ◽  
Energy Levels ◽  
Harmonic Approximation ◽  
Transition Process ◽  
High Energy ◽  
Electronic Energy ◽  
Relaxation Rates ◽  
Conversion Rates

<div>In this work, we propose a new method to calculate the molecular nonradiative electronic relaxation rates based on the numerically exact time-dependent density matrix renormalization group theory (TD-DMRG). This method could go beyond the existing frameworks under the harmonic approximation (HA) of the potential energy surface (PES) so that the important anharmonic effect could be considered when large electronic energy is transferred into the vibrations to excite them to the high energy levels. The effectiveness and scalability of the method are verified in calculating the internal conversion (IC) rate of azulene by comparing it with the analytically exact results under HA. Furthermore, we investigate the validity of HA in a two-mode model with Morse potential. We find that HA is unsatisfactory unless only the lowest several vibrational states of the lower electronic state are involved in the transition process when the adiabatic excitation energy is relatively low. As the excitation energy increases, HA first underestimates and then overestimates the IC rates when the excited state PES shifts towards the dissociative side of the ground state PES. On the contrary, HA slightly overestimates the IC rates when the excited state PES shifts towards the repulsive side. In both cases, higher temperature enlarges the error of HA. <br></div>

scholarly journals Evaluating the Anharmonicity Contributions to the Molecular Excited State Internal Conversion Rates with Finite Temperature TD-DMRG

2021 ◽  
Author(s):  
Yuanheng Wang ◽  
Jiajun Ren ◽  
Zhigang Shuai
Keyword(s):  
Excited State ◽  
Excitation Energy ◽  
Internal Conversion ◽  
Energy Levels ◽  
Harmonic Approximation ◽  
Transition Process ◽  
High Energy ◽  
Electronic Energy ◽  
Relaxation Rates ◽  
Conversion Rates

<div>In this work, we propose a new method to calculate the molecular nonradiative electronic relaxation rates based on the numerically exact time-dependent density matrix renormalization group theory (TD-DMRG). This method could go beyond the existing frameworks under the harmonic approximation (HA) of the potential energy surface (PES) so that the important anharmonic effect could be considered when large electronic energy is transferred into the vibrations to excite them to the high energy levels. The effectiveness and scalability of the method are verified in calculating the internal conversion (IC) rate of azulene by comparing it with the analytically exact results under HA. Furthermore, we investigate the validity of HA in a two-mode model with Morse potential. We find that HA is unsatisfactory unless only the lowest several vibrational states of the lower electronic state are involved in the transition process when the adiabatic excitation energy is relatively low. As the excitation energy increases, HA first underestimates and then overestimates the IC rates when the excited state PES shifts towards the dissociative side of the ground state PES. On the contrary, HA slightly overestimates the IC rates when the excited state PES shifts towards the repulsive side. In both cases, higher temperature enlarges the error of HA. <br></div>

scholarly journals Evaluating the Anharmonicity Contributions to the Molecular Excited State Internal Conversion Rates with Finite Temperature TD-DMRG

2021 ◽  
Author(s):  
Yuanheng Wang ◽  
Jiajun Ren ◽  
Zhigang Shuai
Keyword(s):  
Excited State ◽  
Excitation Energy ◽  
Internal Conversion ◽  
Energy Gap ◽  
Harmonic Approximation ◽  
Transition Process ◽  
Electronic Energy ◽  
Relaxation Rates ◽  
Density Matrix Renormalization ◽  
Conversion Rates

<div>In this work, we propose a new method to calculate the molecular nonradiative electronic relaxation rates based on the numerically exact time-dependent density matrix renormalization group theory (TD-DMRG). This method could go beyond the existing frameworks under the harmonic approximation (HA) of the potential energy surface (PES) so that the anharmonic effect could be considered, which is of vital importance when the electronic energy gap is much larger than the vibrational frequency. We calculate the internal conversion (IC) rates in a two-mode model with Morse potential to investigate the validity of HA. We find that HA is unsatisfactory unless only the lowest several vibrational states of the lower electronic state are involved in the transition process when the adiabatic excitation energy is relatively low. As the excitation energy increases, HA first underestimates and then overestimates the IC rates when the excited state PES shifts towards the dissociative side of the ground state PES. On the contrary, HA slightly overestimates the IC rates when the excited state PES shifts towards the repulsive side. In both cases, higher temperature enlarges the error of HA. As a real example to demonstrate the effectiveness and scalability of the method, we calculate the IC rates of azulene from $S_1$ to $S_0$ on the ab initio anharmonic PES approximated by 1-mode representation. The calculated IC rates of azulene under HA are consistent with the analytically exact results. The rates on anharmonic PES are 30%-40% higher than the rates under HA.</div>

Viscosity dependence of internal conversion rates of polyatomic molecules

1983 ◽  
Vol 78 (3) ◽  
pp. 443-462 ◽  
Author(s):  
K.-E. Süsse ◽  
D.-G. Welsch ◽  
I. Madzgalla
Keyword(s):  
Internal Conversion ◽  
Polyatomic Molecules ◽  
Conversion Rates ◽  
Viscosity Dependence

Organic nanophotonic materials: the relationship between excited-state processes and photonic performances

2016 ◽  
Vol 52 (58) ◽  
pp. 8906-8917 ◽  
Author(s):  
Wei Zhang ◽  
Yong Sheng Zhao
Keyword(s):  
Excited State ◽  
Material Properties ◽  
Related Material ◽  
Organic Nanomaterials ◽  
Molecular Excited State ◽  
The Relationship

Organic active nanophotonics: excited-state coupled photonic behaviours strongly determine the optical performances of organic nanomaterials. The photonic actions and related material properties can be well controlled by tailoring the intra/inter-molecular excited-state processes.

scholarly journals Direct observation of the excited state structure of a Ag(I)-Cu(I) complex

2014 ◽  
Vol 70 (a1) ◽  
pp. C774-C774 ◽  
Author(s):  
Katarzyna Jarzembska ◽  
Radoslaw Kaminski ◽  
Bertrand Fournier ◽  
Elzbieta Trzop ◽  
Jesse Sokolow ◽  
...  
Keyword(s):  
Excited State ◽  
Solid State ◽  
Structural Changes ◽  
Luminescent Properties ◽  
Crystal Form ◽  
Data Sets ◽  
Time Resolved ◽  
Model Complex ◽  
Metal Metal ◽  
Molecular Excited State

Heterodentate coordination complexes have been extensively studied because of their rich electronic and luminescent properties, which are of importance in the design of molecular devices. The short metal-metal contacts found in such complexes determine the nature of the lowest lying emissive states, and must be explored in order to understand their physical properties. Recent advances in time-resolved (TR) synchrotron techniques supported by specific data collection strategies and data processing procedures [1] allow for elucidation of molecular excited state geometries in the solid state. The approach has been so far successfully applied to several high-quality Laue-data sets collected at the 14-ID BioCars beamline at the Advanced Photon Source.[2] In this contribution we present synchrotron TR experiment results obtained for a new solvent-free crystal form of a model complex containing Ag(I) and Cu(I) (Ag2Cu2L4, L = 2-diphenylphosphino-3-methylindole).[3] This system exhibits red solid-state luminescence with a lifetime of about 1 µs. This is one of the shortest-lived excited states we have studied so far with the Laue technique. The relatively short lifetime goes along with significant structural changes observed upon irradiation, such as, the Ag...Ag distance shortening of about 0.2 Å in the excited state. The results clearly show strengthening of the Ag...Ag interactions suggesting a bond formation upon excitation. The photocrystallographic findings are supported by spectroscopic measurements and quantum computations. The results confirm the triplet nature of the emissive state originating mainly from a ligand-to-metal charge transfer. Research funded by the NSF (CHE1213223). BioCARS Sector 14 is supported by NIH, National Center for Research Resources (RR007707). APS is funded by the U.S. DOE, Office of Basic Energy Sciences (W-31-109-ENG-38). KNJ is supported by the Polish Ministry of Science and Higher Education through the "Mobility Plus" program.

Sign in / Sign up

Export Citation Format

Share Document