Related papers: Large-scale correlated study of excited state abso…
In a recently performed experiment Korovyanko et al [Phys. Rev. B 67, 035114 (2003)] have measured the photo-induced absorption (PA) spectrum of phenyl-disubstituted polyacetylenes (PDPA) from 1$B_{u}$ and 2$A_{g}$ excited states. In…
In this paper, we perform large-scale electron-correlated calculations of optoelectronic properties of rectangular graphene-like polycyclic aromatic hydrocarbon molecules. Theoretical methodology employed in this work is based upon…
In this paper we present a detailed theory of the triplet states of oligoacenes containing up to seven rings, i.e., starting from naphthalene all the way up to heptacene. In particular, we present results on the optical absorption from the…
The electronic and optical properties of various polycyclic aromatic hydrocarbons (PAHs) with lower symmetry, namely, benzo[ghi]perylene (C$_{22}$H$_{12}$), benzo[a]coronene (C$_{28}$H$_{14}$), naphtho[2,3a]coronene (C$_{32}$H$_{16}$),…
In this paper we present large-scale correlated calculations of linear optical absorption spectrum of oligo-acenes containing up to seven benzene rings. For the calculations we used the Pariser-Parr-Pople (P-P-P) Hamiltonian, along with the…
Within a rigid-band correlated electron model for oligomers of poly-(paraphenylene) (PPP) and poly-(paraphenylenevinylene) (PPV), we show that there exist two fundamentally different classes of two-photon A$_g$ states in these systems to…
In this paper we present a computational study of linear optical absorption in phenacene class of polyaromatic hydrocarbons. For the purpose, we have employed a correlated-electron methodology based upon configuration-interaction (CI)…
We study the photoabsorption properties of photoactive bulk polymer/ fullerene/nanotube heterojunctions in the near-infrared region. By combining pump-probe spectroscopy and linear response time-dependent density functional theory within…
In this paper we present results of large-scale correlated calculations of triplet photoinduced absorption (PA) spectrum of oligomers of poly-(para)phenylenevinylene (PPV) containing up to five phenyl rings. In particular, the high-energy…
In this paper, optical and electronic properties of diamond shaped graphene quantum dots (DQDs) have been studied by employing large-scale electron-correlated calculations. The computations have been performed using the \pi-electron…
Linear and non-linear spectroscopies are powerful tools used to investigate the energetics and dynamics of electronic excited states of both molecules and crystals. While highly accurate \emph{ab initio} calculations of molecular spectra…
An excitonic method proper to study conjugated oligomers and polymers is described and its applicability tested on the ground state and first excited states of trans-polyacetylene, taken as a model. From the Pariser-Parr-Pople Hamiltonian,…
Model Hamiltonians offer a cost-effective way to capture the key physics of large $\pi$-conjugated systems. In this work, we combine the Pariser--Parr--Pople (PPP) model Hamiltonian with pair Coupled Cluster Doubles (pCCD)-based methods to…
We extend Mulliken's theory of ground state charge transfer in a donor-acceptor complex to excited state charge transfer between pairs of identical $\pi$-conjugated oligomers, one of which is in the optically excited state and the other in…
Two-photon absorption (TPA) and other nonlinear interactions of molecules with time-frequency-entangled photon pairs (EPP) has been predicted to display a variety of fascinating effects. Therefore, their potential use in practical…
We report the linear optical absorption spectra of aluminum clusters Al$_{n}$ (n=2--5) involving valence transitions, computed using the large-scale all-electron configuration interaction (CI) methodology. Several low-lying isomers of each…
We report on direct detection of excited states absorption cross-section using dual wavelength pump-probe technique. Also, we experimentally demonstrate using porphyrin composite molecules (porphyrin derivatives such as…
In this paper, we present a theoretical study of the nonlinear optical response of the newly discovered conjugated polymer poly(diphenyl)polyacetylene (PDPA). In particular, we compute the third-order nonlinear susceptibility corresponding…
In this paper, we present a theoretical investigation of photoabsorption spectrum of the newly synthesized hydrogenated cluster of aluminium, Al4H6. The calculations are performed within the wave-function-based semi-empirical method…
The photo-fragmentation spectrum of protonated fluorene has been recorded in the visible spectral region, largely red shifted as compared to the first excited state absorption of neutral fluorene. The spectrum shows two different…