Analysis of the Results of the Borowiec SLR Station (7811) for the Period 1993–2019 as an Example of the Quality Assessment of Satellite Laser Ranging Stations

This paper presents the results of an orbital analysis of satellite laser ranging data performed by the Borowiec SLR station (7811) in the period from July 1993 to December 2019, including the determination of the station positions and velocity. The analysis was performed using the GEODYN-II orbital program for the independent monthly orbital arcs from the results of the LAGEOS-1 and LAGEOS-2 satellites. Each arc was created from the results of the laser observations of a dozen or so selected stations, which were characterized by a large number of normal points and a good quality of observations. The geocentric and topocentric coordinates of the station were analyzed. Factors influencing the uncertainty of the measurements were determined: the number of the normal points, the dispersion of the normal points in relation to the orbits, and the long-term stability of the systematic deviations. The position leap at the end of 2002 and its interpretation in ITRF2014 were analyzed. The 3D stability of the determined positions throughout the period of study was equal to 12.7 mm, with the uncertainty of determination being at the level of 4.3 mm. A very high compliance of the computed velocity of the Borowiec SLR station (24.9 mm/year) with ITRF2014 (25.0 mm/year) was found.

DFT Based Modeling of Asymmetric Non-Fullerene Acceptors for High-Performance Organic Solar Cell

AbstractFive new asymmetric NFA-based polymer solar cells i.e., N1-N5 are designed by doing modification in terminal groups of the acceptor part of experimentally synthesized reference molecule with (4,4,9,9-tetramethyl-4,9 dihydroselenopheno [2’,3’:5,6]-s-indaceno [1,2-b] thiophene) core. Frontier molecular orbital analysis is used to study their photovoltaic and optoelectronic properties. It confirmed the electrons' transportation from the donor to the acceptor part. It stated that all molecules have a lower bandgap than R and N2 has the lowest bandgap of 2.01 eV. The molecular orbital potential analysis confirmed the electron-withdrawing properties of the terminal groups. Optical properties studies evaluated maximum absorption with transition energies. All newly designed molecules N1-N5 show higher λmax values than R i.e., in the range of 680-740 nm with N2 having the highest λmax of 735 nm and lowest transition energy of 1.69 eV. Dipole moment studies showed that N3 has a maximum dipole moment of 7-40 D with all others having comparable values. TDM plots confirmed the electron shifting from donor to acceptor region. Reorganization energy analysis showed that N1 and N3 have the lowest reorganization energy values thus giving the highest electron mobilities. Voc calculated results of all molecules N1-N5 have lower values than R when coupled with PTB7-Th donor polymer. Charge transport analysis of N2 and PTB7-Th coupled molecule confirmed the acceptor type nature of our designed molecules.

Investigations on spectroscopic characterizations, molecular docking, NBO, drug-Likeness, and ADME properties of 4H-1,2,4-triazol-4-amine by combined computational approach

In this study, the spectroscopic characterization, frontier molecular orbital analysis, and natural bond orbital analysis (NBO) analysis were executed to determine the movement of electrons within the molecule and the stability, and charge delocalization of the 4H-1,2,4-triazol-4-amine (4-AHT) through density functional theory (DFT) approach and B3LYP/6-311++G(d,p) level of theory. Surface plots of the hybrids’ Molecular Electrostatic Potential (MEP) revealed probable electrophilic and nucleophilic attacking sites. The discussed ligand were observed to be characterized by various spectral studies (FT-IR, UV-Vis). The calculated IR was found to be correlated with experimental values. The UV-Vis data of the molecule was used to analyze the visible absorption maximum (λmax) using the time-dependent DFT method. Since the principle of drug-likeness is usually used in combinatorial chemistry to minimize depletion in pharmacological investigations and growth, drug-likeness and ADME properties were calculated in this research to establish 4-AHT molecule bioavailability. Furthermore, molecular docking studies were carried out. Molecular docking analysis was performed for the title ligand inside the active site of the Epidermal Growth Factor Receptor (EGFR). The title compound’s anti-tumor activity against the cancer cell, in which EGFR is strongly expressed, prompted us to conduct molecular docking into the ATP binding site of EGFR to predict whether this molecule has an analogous binding mode to the EGFR inhibitors (PDB: ID: 1M17).

On the Quantum Chemical Nature of Lead(II) “Lone Pair”

We study the quantum chemical nature of the Lead(II) valence basins, sometimes called the lead “lone pair”. Using various chemical interpretation tools, such as molecular orbital analysis, natural bond orbitals (NBO), natural population analysis (NPA) and electron localization function (ELF) topological analysis, we study a variety of Lead(II) complexes. A careful analysis of the results shows that the optimal structures of the lead complexes are only governed by the 6s and 6p subshells, whereas no involvement of the 5d orbitals is found. Similarly, we do not find any significant contribution of the 6d. Therefore, the Pb(II) complexation with its ligand can be explained through the interaction of the 6s2 electrons and the accepting 6p orbitals. We detail the potential structural and dynamical consequences of such electronic structure organization of the Pb (II) valence domain.

Diagnosis of Mechanical Faults Affecting a Hydroelectric Group by Vibration Analysis

This article deals with a diagnostic approach based on a predictive / conditional maintenance approach of a hydroelectric group. The technique used is based on the spectral analysis of the vibration signals, as well as on the orbital analysis of the bearings displacements. To do this, test protocols in different operating regimes are carried out, based on the collection of data measured according to the multisensor approach, the aim of which is to identify the predominant faults. The positions of the sensors are placed as close as possible to the bearings on the rigid structure of the hydroelectric group in accordance with the recommendations of standard ISO 10816-5. The evaluation approach is based on the analysis of the amplitudes of the vibration speeds, the aim of which is to identify the type of faults, as well as on the bearing displacement indicators in order to classify them in the pre-established zones according to thresholds recommended by the Standard. Therefore, a recommended tuning intervention can be planned in order to restore the unit to its proper operating condition, the aim of which is to increase its service life and improve fuel efficiency. Keywords—Diagnostic, Vibration analysis, Hydroelectric group, Multi-sensor approach, Standard

Flexible boundary layer using exchange for embedding theories. II. QM/MM dynamics of the hydrated electron

The FlexiBLE embedding method introduced in the preceding companion paper [Z. Shen and W. J. Glover, J. Chem. Phys. X, X (2021)] is applied to explore the structure and dynamics of the aqueous solvated electron at an all-electron density functional theory QM/MM level. Compared to a one-electron mixed quantum/classical description, we find the dynamics of the many-electron model of the hydrated electron exhibits enhanced coupling to water OH stretch modes. Natural Bond Orbital analysis reveals this coupling is due to significant population of water OH σ* orbitals, reaching 20%. Based on this, we develop a minimal frontier orbital picture of the hydrated electron involving a cavity orbital and important coupling to 4-5 coordinating OH σ* orbitals. Implications for the interpretation of the spectroscopy of this interesting species are discussed.

Flexible boundary layer using exchange for embedding theories. II. QM/MM dynamics of the hydrated electron

The FlexiBLE embedding method introduced in the preceding companion paper [Z. Shen and W. J. Glover, J. Chem. Phys. X, X (2021)] is applied to explore the structure and dynamics of the aqueous solvated electron at an all-electron density functional theory QM/MM level. Compared to a one-electron mixed quantum/classical description, we find the dynamics of the many-electron model of the hydrated electron exhibits enhanced coupling to water OH stretch modes. Natural Bond Orbital analysis reveals this coupling is due to significant population of water OH σ* orbitals, reaching 20%. Based on this, we develop a minimal frontier orbital picture of the hydrated electron involving a cavity orbital and important coupling to 4-5 coordinating OH σ* orbitals. Implications for the interpretation of the spectroscopy of this interesting species are discussed.

Shedding Light on the Optical and Nonlinear Optical Properties of Super-Alkali Doped Borophene

The present investigation highlights the 2-dimentional design of several interesting super alkali doped borophene derivatives for efficient nonlinear optical (NLO). Borophene (B36) and super alkali units (Li3O) whose combining effects and resulting NLO responses have been evaluated by orienting super-alkali clusters at various sites such as a hub, rim, and bridged around the B36 molecule. The charge analysis is characterized by frontier and natural bond orbital analysis, narrowed HOMO-LUMO band gap, better intramolecular charge transfers. Molecular electrostatic potential surfaces demonstrate enhanced optoelectronic features of these complexes that are viable owing to Li3O adsorption. Singly doped and doubly doped complexes have been considered and their NLO properties have been calculated. Band gap energy reduces about three times when doped with two Li3O. A considerably high figure of merit, first hyperpolarizability (bo) values up to five digits 10611 a. u. for complex A proved that these systems can be utilized as promising candidates in various NLO applications.

Flexible boundary layer using exchange for embedding theories. II. QM/MM dynamics of the hydrated electron

The FlexiBLE embedding method introduced in the preceding companion paper [Z. Shen and W. J. Glover, J. Chem. Phys. X, X (2021)] is applied to explore the structure and dynamics of the aqueous solvated electron at an all-electron density functional theory QM/MM level. Compared to a one-electron mixed quantum/classical description, we find the dynamics of the many-electron model of the hydrated electron exhibits enhanced coupling to water OH stretch modes. Natural Bond Orbital analysis reveals this coupling is due to significant population of water OH σ* orbitals, reaching 20%. Based on this, we develop a minimal frontier orbital picture of the hydrated electron involving a cavity orbital and important coupling to 4-5 coordinating OH σ* orbitals. Implications for the interpretation of the spectroscopy of this interesting species are discussed.

Lanthanum- Oligopyrrole Complexes (neutral, III) for biogas capture applications by DFT

The structures and interactions of systems formed by the MPBCP (meta-Phenylene-Bridged Cyclic Oligopyrrole) functionalized with lanthanum atom were studied for investigating the abilities of MPBCP, [La-MPBCP]+3 and La-MPBCP to absorb biogas (CO2, N2, H2 and CH4) using density functional theory. The Eads calculated values for biogas molecules on [La-MPBCP]+3 and La-MPBCP showed that these gas molecules have favorable interactions with the lanthanum atom coordinated on the MPBCP. CO2 molecule shows strong interactions, with Eads values of -28.63 and -15.95 kcal/mol. In the case of H2 molecule, the Eads is lower with values of -7.51 and -5.28. It is easy to observe the CO2 molecule on the [La-MPBCP]+3 system has four times higher energy value than adsorption energy for the H2 molecule. The natural bond orbital analysis reveals that gas molecules are electron donator in the systems and the acceptor orbitals belong to lanthanum atom. Computational studies suggest that CO2, N2, CH4 and H2 molecules on [La-MPBCP]+3 and La-MPBCP present physisorption. Our findings divulge promising potential of the [La-MPBCP]+3 as an adsorber/separator CO2/H2.