Excited states dynamics of polydiacetylenes: An <i>ab initio</i> and femtosecond spectroscopic investigation of the change from the acetylenic to the butatrienic structure

Excitation energies of pi-conjugated oligomers within time-dependent current-densityfunctional theory van Faassen, M.; de Boeij, P. L. Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum. We study the *← singlet excitations of the -conjugated oligomers of polyacetylene, polydiacetylene, polybutatriene, polythiophene, poly͑para-phenylene vinylene͒, and the lowest singlet excitations of the hydrogen chain. For this we used time-dependent current-density-functional theory within the Vignale-Kohn and adiabatic local density approximations. By studying the dependence of the excitation spectrum on the chain length we conclude that the reduction of the static polarizability when using the Vignale-Kohn functional has two origins. First, the excitation energies of transitions with a large transition dipole are shifted upward. Second, the character of the transition between the lowest occupied and highest unoccupied molecular orbitals and the oscillator strength of the lowest transition within the adiabatic local density approximation is transferred to higher transitions. The lowest transitions that have a considerable oscillator strength obtained with the Vignale-Kohn functional have excitation energies that are in most cases in better agreement with available reference data than the adiabatic local density approximation.

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“…47 The CASPT2 values are considered the most accurate according to Ref. 47. There are also CCSD results available for the monomers.…”

Section: Resultsmentioning

confidence: 99%

“…Some CASSCF and CASPT2 results for the 1 1 AЈ excitation energies of PDA and the 1 1 B u excitation energies of PDA were available from the literature for the shorter chains. 47 The CASPT2 values are considered the most accurate according to Ref. 47.…”

Section: Resultsmentioning

confidence: 99%

Excitation energies of π-conjugated oligomers within time-dependent current-density-functional theory

Faassen

Boeij

2004

The Journal of Chemical Physics

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“…The two key requirements for highly efficient luminescent materials are: (i) the strongly dipole-allowed transition from the lowest excited singlet state (S 1 ) to the ground state (S 0 ) according to Kasha's rule, which has been widely applied to the luminescent conjugated materials 10 and (ii) the high a) Author to whom correspondence should be addressed. Electronic mail:…”

Section: Introductionmentioning

confidence: 99%

Theoretical predictions of red and near-infrared strongly emitting X-annulated rylenes

Peng

Niu

Wang

et al. 2011

The Journal of Chemical Physics

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The optical properties of rylenes are extremely interesting because their emission colors can be tuned from blue to near-infrared by simply elongating the chain length. However, for conjugated chains, the dipole-allowed odd-parity 1B u excited state often lies above the dipole-forbidden evenparity 2A g state as the chain length increases, thus preventing any significant luminescence according to Kasha's rule. We systemically investigated the 1B u /2A g crossover behaviors with respect to the elongating rylene chain length with various quantum chemistry approaches, such as timedepended density functional theory (TDDFT), complete active space self-consistent field theory (CASSCF/CASPT2), multireference configuration interaction (MRCI)/Zerner's intermediate neglect of diatomic overlap (ZINDO), and MRCI/modified neglect of differential overlap. The calculated results by CASSCF/CASPT2 and MRCI/ZINDO are completely coherent: the optical active 1B u state lies below the dark B 3g or 2A g state for perylene and terrylene, which results in strong fluorescence; while a crossover to S 1 = 2A g occurs and leads to much weaker fluorescence for quaterrylene. Then we put forward a molecular design rule on how to recover fluorescence for the longer rylenes by introducing heteroatom bridges. Several heteroatom-annulated rylenes are designed theoretically, which are predicted to be strongly emissive in the red and near-infrared ranges. These are further confirmed by theoretical emission spectra as well as radiative and nonradiative decay rate calculations by using the vibration correlation function formalisms we developed earlier coupled with TDDFT.

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“…In the probe-photon energy region below 1.90 eV the normalized difference transmittance signals are negative due to the photoinduced transition from the geometrically relaxed 2 1 A g state to the higher excited nB u state which is one of the four essential states [30,42]. The 1 1 B u -FE state decays within 100 fs into the geometrically relaxed 2 1 A g state [2,31,43]. The power spectrum of Fourier transform of DT(t)=T at 128 probephoton energies probed by using the multi-channel lock-in amplifier is shown in Figure 4.…”

Section: Methodsmentioning

confidence: 96%

Ultrafast Optical Nonlinearity in Polydiacetylenes Studied by Sub-5-fs Laser

Kobayashi

Ikuta

2006

Molecular Crystals and Liquid Crystals

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Molecular vibration of several modes in blue-phase polydiacetylene-3-butoxycarbonylmethylurethane (PDA-3BCMU) was real-time observed by 5-fs pump-probe measurement. The contribution of the vibrational wavepackets in the ground state and in the excited state in the signal were separated by multichannel measurements The C=C stretching mode in the ground state starts to oscillate p-out-ofphase with the CC stretching mode. The structure of PDA-3BCMU in the geometrically relaxed state is not pure butatriene-type but more like acetylene-type. The frequencies of C=C and CC stretching modes there were determined by singular value decomposition method to be 1472 AE 6 cm À1 and 2092 AE 6 cm À1 , respectively. The double and triple bond stretching frequencies in the ground state which are 1463 AE 6 cm À1 and 2083 AE 6 cm À1 , respectively.

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Excited states dynamics of polydiacetylenes: An ab initio and femtosecond spectroscopic investigation of the change from the acetylenic to the butatrienic structure

Cited by 15 publications

References 49 publications

Excitation energies of π-conjugated oligomers within time-dependent current-density-functional theory

Excitation energies of π-conjugated oligomers within time-dependent current-density-functional theory

Theoretical predictions of red and near-infrared strongly emitting X-annulated rylenes

Ultrafast Optical Nonlinearity in Polydiacetylenes Studied by Sub-5-fs Laser

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