Sina Yeganeh

Learn More
A summary of the technical advances that are incorporated in the fourth major release of the Q-CHEM quantum chemistry program is provided, covering approximately the last seven years. These include developments in density functional theory methods and algorithms, nuclear magnetic resonance (NMR) property evaluation, coupled cluster and perturbation(More)
This article shows that, although Boys localization is usually applied to single-electron orbitals, the Boys method itself can be applied to many electron molecular states. For the two-state charge-transfer problem, we show analytically that Boys localization yields the same charge-localized diabatic states as those found by generalized Mulliken-Hush(More)
We present a model for the transmission of spin-polarized electrons through oriented chiral molecules, where the chiral structure is represented by a helix. The scattering potential contains a confining term and a spin-orbit contribution that is responsible for the spin-dependent scattering of electrons by the molecular target. The differential scattering(More)
Time-resolved transient optical absorption and EPR (TREPR) spectroscopies are used to probe the interaction of the lowest excited singlet state of perylene-3,4:9,10-bis(dicarboximide) ((1*)PDI) with a stable tert-butylphenylnitroxide radical ((2)BPNO(*)) at specific distances and orientations. The (2)BPNO(*) radical is connected to the PDI with the(More)
Here, means to enhance power conversion efficiency (PCE or h) in bulkheterojunction (BHJ) organic photovoltaic (OPV) cells by optimizing the series resistance (Rs)—also known as the cell internal resistance—are studied. It is shown that current state-of-the-art BHJ OPVs are approaching the limit for which efficiency can be improved via Rs reduction alone.(More)
We report a simple and reproducible method for fabricating heterometallic nanogaps, which are made of two different metal nanorods separated by a nanometer-sized gap. The method is based upon on-wire lithography, which is a chemically enabled technique used to synthesize a wide variety of nanowire-based structures (e.g., nanogaps and disk arrays). This(More)
Click to fill the gap: The in situ modular fabrication of molecular transport junctions in nanogaps generated by on-wire lithography is achieved by using click chemistry (see picture). The formation of molecular junctions proceeds in high yields and can be used to test different molecules; the triazole group also maintains conjugation in the molecular(More)
We discuss several proposed explanations for the switching and negative differential resistance (NDR) behavior seen in some molecular junctions. Several theoretical models are discussed, and we present results of electronic structure calculations on a series of substituted oligo(phenylene ethynylene) molecules. It is shown that a previously proposed polaron(More)
Organic semiconductors (OSCs) have recently received significant attention for their potential use in photovoltaic, light emitting diode, and field effect transistor devices. Part of the appeal of OSCs is the disordered, amorphous nature of these materials, which makes them more flexible and easier to process than their inorganic counterparts. In addition(More)
The effect of anharmonicity in the intramolecular modes of a model system for exothermic intramolecular nonadiabatic electron transfer is probed by examining the dependence of the transition probability on the exoergicity. The Franck-Condon factor for the Morse potential is written in terms of the Gauss hypergeometric function both for a ground initial(More)