Multireference Fock Space Coupled-Cluster Method for the (3,0) Sector.

This work reports an implementation of a novel realization of the multireference coupled cluster theory formulated in Fock space. Extending the previous formulation carried out in the (1,1) [M. Musial, R.

Direct spectroscopic evidence of the crucial role played by surface oxygen vacancies in the O-sensing mechanism of SnO.

Conductometric gas sensors (CGS) provide a reproducible gas response at a low cost but their operation mechanisms are still not fully understood. In this paper, we elucidate the nature of interactions between SnO, a common gas-sensitive material, and O, a ubiquitous gas central to the detection mechanisms of CGS. Using synchrotron radiation, we investigated a working SnO sensor under operando conditions near-ambient pressure (NAP) XPS with simultaneous resistance measurements, and created a depth profile of the variable near-surface stoichiometry of SnO as a function of O pressure.

Electronic states of NaLi molecule: Benchmark results with Fock space coupled cluster approach.

Accurate potential energy curves (PECs) are obtained for 20 lowest lying electronic states of the NaLi molecule. The computational scheme used here is based on the multireference coupled cluster theory formulated in the (2,0) sector of the Fock space. The latter sector provides the description of states obtained by attachment of two electrons to the reference system.

Extension of the Fock-space coupled-cluster method with singles and doubles to the three-valence sector.

The single-reference coupled-cluster method has proven very effective in the ab initio description of atomic and molecular systems, but its successful application is limited to states dominated by a single Slater determinant, which is used as the reference. In cases where several determinants are important in the wave function expansion, i.e.

Chinchilla (Chinchilla lanigera) behavioral responses to a visual signal preceding handling.

Zoos use ambassador animals in educational programs featuring close contact with humans. Chinchillas (Chinchilla lanigera) at the Saint Louis Zoo are retrieved for programs by a keeper wearing brown handling gloves, but green cleaning gloves are worn during normal husbandry when physical contact with the animal is only incidental. The chinchillas' primary keeper anecdotally reported more reactivity and movement from chinchillas when approached with handling gloves.

Balancing Overscreening and Underdiagnosis in Secondary Hypertension: The Case of Fibromuscular Dysplasia.

Knowledge about fibromuscular dysplasia (FMD) has broadened over the last several decades. It is no longer considered a rare and benign entity limited to renal arteries and causing just hypertension. It affects other parts of the arterial tree nearly as frequently as the renal arteries.

Potential Energy Curves for the Low-Lying Electronic States of K from ab Initio Calculations with All Electrons Correlated.

The electron affinity (EA) calculations based on the equation-of-motion coupled cluster method proved to be an efficient scheme in the treatment of potential energy curves (PECs) for alkali molecular ions, Me. The EA approach provides description of states obtained by an attachment of one electron to the reference, which for the Me is a doubly ionized Me system. The latter has a very concrete advantage in the calculations of the PECs, since it dissociates into the closed-shell fragments (Me → Me + Me); hence, the restricted Hartree-Fock reference can be used in the whole range of interatomic distances.

Morphometric and mechanical characteristics of Equisetum hyemale stem enhance its vibration.

The order of the internodes, and their geometry and mechanical characteristics influence the capability of the Equisetum stem to vibrate, potentially stimulating spore liberation at the optimum stress setting along the stem. Equisetum hyemale L. plants represent a special example of cellular solid construction with mechanical stability achieved by a high second moment of area and relatively high resistance against local buckling.

Equation-of-motion coupled cluster method for the description of the high spin excited states.

The equation-of-motion (EOM) coupled cluster (CC) approach in the version applicable for the excitation energy(EE) calculations has been formulated for high spin components. The EE-EOM-CC scheme based on the restricted Hartree-Fock reference and standard amplitude equations as used in the Davidson diagonalization procedure yields the singlet states. The triplet and higher spin components require separate amplitude equations.

Are trichomes involved in the biomechanical systems of Cucurbita leaf petioles?

Trichomes are involved in petiole movement and likely function as a part of the plant biomechanical system serving as an additional reservoir of hydrostatic pressure. The large, non-glandular trichomes on Cucurbita petioles occur across collenchyma strands. Time-lapse imaging was used to study the leaf reorientation of Cucurbita maxima 'Bambino' plants placed in horizontal position.

Equation-of-motion coupled cluster method for high spin double electron attachment calculations.

The new formulation of the equation-of-motion (EOM) coupled cluster (CC) approach applicable to the calculations of the double electron attachment (DEA) states for the high spin components is proposed. The new EOM equations are derived for the high spin triplet and quintet states. In both cases the new equations are easier to solve but the substantial simplification is observed in the case of quintets.

First Principle Calculations of the Potential Energy Curves for Electronic States of the Lithium Dimer.

A multireference coupled cluster (CC) approach formulated in the (2,0) sector of the Fock space (FS) is applied to study electronic states of the Li2 molecule. The CC model including single (S) and double (D) excitations from the reference configuration is considered. The FS-CCSD(2,0) method is applicable to the description of the double electron attached states, which implies that in the neutral molecule studies the doubly ionized reference should be adopted.

Solvatochromism effects on the dipole moments and photo-physical behavior of some azo sulfonamide dyes.

Absorption and emission spectra of three azo sulfonamide dyes with various molecular structures have been studied in different solvents. The solute photo-physical behavior depends strongly on the solvent-solute interactions and solvent microenvironment. In order to understand the effect of intermolecular interactions on spectral behaviors of these dyes in different solvents and to conceive nature and extent of solvent-solute interactions the spectral variations were analyzed by the linear solvation energy relationships concept.

Multireference Double Electron Attached Coupled Cluster Method with Full Inclusion of the Connected Triple Excitations: MR-DA-CCSDT.

The multireference (MR) double electron attached (DA) coupled cluster (CC) method with full inclusion of the connected triple excitations has been applied to study various kinds of MR situations. The MR-DA-CCSDT (S, Singles; D, Doubles; T, Triples) equations have been derived and implemented in an efficient way with n(6) scaling for the target multireference states. They can be used for producing potential energy curves (PECs) for some classes of molecules, e.

Adsorption kinetics of ultrathin polymer films in the melt probed by dielectric spectroscopy and second-harmonic generation.

We studied the adsorption kinetics of supported ultrathin films of dye-labeled polystyrene (l-PS) by combining dielectric spectroscopy (DS) and the interface-specific nonlinear optical second harmonic generation (SHG) technique. While DS is sensitive to the fraction of mobile dye moieties (chromophores), the SHG signal probes their anisotropic orientation. Time-resolved measurements were performed above the glass transition temperature on two different sample geometries.

Photo-responsive polymer with erasable and reconfigurable micro- and nano-patterns: an in vitro study for neuron guidance.

The interaction of cells with nanoscale topography has proven to be an important modality in controlling cell responses. Topographic parameters on material surfaces play a role in cell growth. We have synthesized a new bio compatible polymer containing photoswitching molecules.

Excited and ionized states of the ozone molecule with full triples coupled cluster methods.

The role of connected triple excitations in coupled cluster (CC) calculations of vertical excitation energies, ionization potentials, and the electron affinity of the ozone molecule is evaluated. The equation of motion (EOM) and Fock space (FS) multireference CC approaches with full triples have been used in the calculations. The effect of the T(3) and R(3) operators significantly improve the EOM CCSD results for all considered quantities.

Cognitive ability experiment with photosensitive organic molecular thin films.

We present an optical experiment which permits us to evaluate the information exchange necessary to self-induce cooperatively a well-organized pattern in a randomly activated molecular assembly. A low-power coherent beam carrying polarization and wavelength information is used to organize a surface relief grating on a photochromic polymer thin film which is photoactivated by a powerful incoherent beam. We demonstrate experimentally that less than 1% of the molecules possessing information cooperatively transmit it to the entire photoactivated polymer film.

Experimental and theoretical UV characterizations of acetylacetone and its isomers.

Cryogenic matrix isolation experiments have allowed the measurement of the UV absorption spectra of the high-energy non-chelated isomers of acetylacetone, these isomers being produced by UV irradiation of the stable chelated form. Their identification has been done by coupling selective UV-induced isomerization, infrared spectroscopy, and harmonic vibrational frequency calculations using density functional theory. The relative energies of the chelated and non-chelated forms of acetylacetone in the S0 state have been obtained using density functional theory and coupled-cluster methods.

Nonlocal communication with photoinduced structures at the surface of a polymer film.

Nonlocal communication between two laser light beams is experimented in a photochromic polymer thin films. Information exchange between the beams is mediated by the self-induction of a surface relief pattern. The exchanged information is related to the pitch and orientation of the grating.

Incoherent light-induced self-organization of molecules.

Although coherent light is usually required for the self-organization of regular spatial patterns from optical beams, we show that peculiar light-matter interaction can break this evidence. In the traditional method of recording laser-induced periodic surface structures, a light intensity distribution is produced at the surface of a polymer film by an interference between two coherent optical beams. We report on the self-organization followed by propagation of a surface relief pattern.

Multistate polarization addressing using a single beam in an azo polymer film.

Peculiar light-matter interactions can break the rule that a single beam polarization can address only two states in an optical memory device. Multistate storage of a single beam polarization is achieved using self-induced surface diffraction gratings in a photoactive polymer material. The grating orientation follows the incident light beam's polarization direction.

Molecular applications of the intermediate Hamiltonian Fock-space coupled-cluster method for calculation of excitation energies.

The intermediate Hamiltonian Fock-space coupled-cluster (FS-CC) method with singles and doubles is applied to calculate vertical excitation energies (EEs) for some molecular systems. The calculations are performed for several small molecules, such as H2O, N2, and CO, and for larger systems, such as C2H4, C4H6, and C6H6. Due to the intermediate Hamiltonian formulation, which provides a robust computational scheme for solving the FS-CC equations, and the efficient factorization strategy, relatively large basis sets and model spaces are employed permitting a comparison of the calculated vertical EEs with the experimental data.