CEO/semiempirical calculations of UV–visible spectra in conjugated molecules

Tretiak, Sergei; Saxena, Avadh; Martin, Richard L.; Bishop, A. R.

doi:10.1016/s0009-2614(00)01009-5

Cited by 31 publications

(36 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…S 2 (p,p Ã ) transition we have observed a red shift of 11 nm as mean value. Moreover, because the theoretical mean deviation on the transition energy of the INDO/S-CIS calculations is close to 0.1 eV, [25] whereas the spectral range under study represents 7 to 10 nm, consequently, the theoretical data agree very well with the experimental measurements. Although hydrogen bonds are not involved in the computational calculations, the solvent effect defined by means of the reaction field is adequate enough to improve the spectral shift observed in the 1 S 0 !…”

Section: Resultssupporting

confidence: 56%

¹π→¹π* Ultraviolet Absorption Bands and Electronic Charge Transfers in Singlet Excited States of Sulfur Aromatic Heterocycles

Araya

Vargas

Morales

2005

Spectroscopy Letters

View full text Add to dashboard Cite

Indoline-2-thione (BC), benzimidazole-2-thione (BN), benzoxazole-2-thione (BO), and benzothiazole-2-thione (BS) define an interesting series of aromatic compounds containing a NCS synthonic unit in a heterocyclic ring of five centers, substituted by atomic centers of the type C, N, O, or S, where the main electronic absorption bands are localized in the spectral range of ultraviolet A or B.The first two singlet electronic transitions of this series, 1 S 0 ! 1 S 1 (n,p Ã ) and 1 S 0 ! 1 S 2 (p,p Ã ), determine the main spectroscopic characteristic of these compounds in order to be used as potential photochemical actinometers of solar ultraviolet radiation. Furthermore, the second electronic transition, localized in the 270-360 nm ultraviolet spectral range, presents a hipsochromic spectral shift as function of the electronic nature of the heteroatomic centers in the heterocyclic ring. In order to determine a spectroscopic assignment of the main absorption bands in aqueous solution and analyze the effect of the substituent on the electronic charge distributions in the ground and the first two singlet excited electronic states, we have used a semiempirical molecular orbital calculation in the INDO/S-CIS approach. On the other hand, we have carried out a molecular orbital calculation in the AM1 framework, in order to determine the energetic stability of the thiones with respect to the thiol compounds.

show abstract

Section: Resultssupporting

confidence: 56%

¹π→¹π* Ultraviolet Absorption Bands and Electronic Charge Transfers in Singlet Excited States of Sulfur Aromatic Heterocycles

Araya

Vargas

Morales

2005

Spectroscopy Letters

View full text Add to dashboard Cite

show abstract

“…in a variety of molecules (46). In addition, this model provides a reasonable accuracy for excited-state properties in combination with the random-phase approximation (53,54). The calculations start from the optimal geometry of a linear cis-polyacetylene oligomer obtained with the standard GAUSSIAN 98 computational package (36), i.e., the ground-state potential energy E g (q) is minimal in the space of nuclear coordinates q, which span the 3N Ϫ 6-dimensional space, with N being the total number of atoms in the molecule.…”

Section: Resultsmentioning

confidence: 88%

Photoexcited breathers in conjugated polyenes: An excited-state molecular dynamics study

Tretiak

Saxena²,

Martin³

et al. 2003

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

View full text Add to dashboard Cite

-conjugated polymers have become an important class of materials for electronic devices. Design of these devices requires understanding such processes as photochemical reactions, spatial dynamics of photoexcitations, and energy and charge transport, which in turn involve complex coupled electron-vibrational dynamics. Here we study nonlinear photoexcitation dynamics in the polyene oligomers by using a quantum-chemical method suitable for the simulation of excitedstate molecular dynamics in extended molecular systems with sizes up to hundreds of atoms. The method is based on the adiabatic propagation of the ground-state and transition single-electron density matrices along the trajectory. The simulations reveal formation of a self-localized vibronic excitation (''breather'' or multiquanta bound state) with a typical period of 34 fs and allows us to identify specific slow and fast nuclear motions strongly coupled to the electronic degrees of freedom. The effect of chain imperfections and chemical defects on the dynamics is also investigated. A complementary two-dimensional analysis of corresponding transition density matrices provides an efficient way to monitor time-dependent real-space localization of the photoexcitation by identifying the underlying changes in charge densities and bond orders. Possible correlated electronic and vibrational spectroscopic signatures of photoexcited breathers are predicted, and generalizations to energy localization in complex macromolecules are discussed.T he science and technology of electronic and optoelectronic devices based on organic -conjugated polymers is evolving rapidly. Numerous high-performance photonic devices fabricated from organic polymers and molecular crystals have been made (1, 2), including light-emitting diodes (LEDs) (2-8) and electrochemical cells (9), display panels (10-12), photovoltaic cells (13-15), photodetectors (16-18), transistors (19-21), lightemitting field-effect transistors (22), biosensors (23), imaging devices (24, 25), and solid-state lasers (26-29). The rational design of novel plastic materials with enhanced functionalities requires insight into their electronic structure, charge and energy transport, and photoexcitation dynamics. This study has become a research frontier that involves many challenges for theory, experiment, and synthesis; however, a sufficient fundamental understanding is yet to be achieved.The theoretical description of -conjugated molecular systems is challenging because of electronic correlation effects and strong electron-phonon interactions. It is well understood from the early days of polyacetylene studies (1, 30) that coupling of the electrons to the nuclear degrees of freedom results in a very rich photophysics of solitons, polarons, and excitons and makes an important distinction of ''soft'' condensed matter from rigid solids based on semiconductor or crystalline metal materials. On the other hand, electron correlation effects have a dramatic impact on the electronic structure, leading, e.g., to the inverse ordering...

show abstract

“…Similarly, TD-AM1 calculations have significantly less computational cost but with reduced accuracy in comparison to TD-DFT [34,35]. In comparison to experimental optical spectra, TD-AM1 performs quite well for conjugated organic molecules such as those studied in this work [36,37,34].…”

Section: Excited State Molecular Dynamics Simulationsmentioning

confidence: 85%

Simulations of fluorescence solvatochromism in substituted PPV oligomers from excited state molecular dynamics with implicit solvent

Bjorgaard

Nelson

Kalinin

et al. 2015

Chemical Physics Letters

Self Cite

View full text Add to dashboard Cite

a b s t r a c tAn efficient method of treating solvent effects in excited state molecular dynamics (ESMD) is implemented and tested by exploring the solvatochromic effects in substituted p-phenylene vinylene oligomers. A continuum solvent model is used which has very little computational overhead. This allows simulations of ESMD with solvent effects on the scale of hundreds of picoseconds for systems of up to hundreds of atoms. At these time scales, solvatochromic shifts in fluoresence spectra can be described. Solvatochromic shifts in absorption and fluorescence spectra from ESMD are compared with time-dependent density functional theory calculations and experiments.

show abstract

CEO/semiempirical calculations of UV–visible spectra in conjugated molecules

Cited by 31 publications

References 29 publications

¹π→¹π* Ultraviolet Absorption Bands and Electronic Charge Transfers in Singlet Excited States of Sulfur Aromatic Heterocycles

¹π→¹π* Ultraviolet Absorption Bands and Electronic Charge Transfers in Singlet Excited States of Sulfur Aromatic Heterocycles

Photoexcited breathers in conjugated polyenes: An excited-state molecular dynamics study

Simulations of fluorescence solvatochromism in substituted PPV oligomers from excited state molecular dynamics with implicit solvent

Contact Info

Product

Resources

About

CEO/semiempirical calculations of UV–visible spectra in conjugated molecules

Cited by 31 publications

References 29 publications

1π→1π* Ultraviolet Absorption Bands and Electronic Charge Transfers in Singlet Excited States of Sulfur Aromatic Heterocycles

1π→1π* Ultraviolet Absorption Bands and Electronic Charge Transfers in Singlet Excited States of Sulfur Aromatic Heterocycles

Photoexcited breathers in conjugated polyenes: An excited-state molecular dynamics study

Simulations of fluorescence solvatochromism in substituted PPV oligomers from excited state molecular dynamics with implicit solvent

Contact Info

Product

Resources

About

¹π→¹π* Ultraviolet Absorption Bands and Electronic Charge Transfers in Singlet Excited States of Sulfur Aromatic Heterocycles

¹π→¹π* Ultraviolet Absorption Bands and Electronic Charge Transfers in Singlet Excited States of Sulfur Aromatic Heterocycles