Super alkali (OLi3) doped boron nitride with enhanced nonlinear optical behavior

In this study, density functional theory is used to examine the electronic and nonlinear optical properties of a narrative class boron nitride (B[Formula: see text]N[Formula: see text]) doped with super alkali OLi3. From the computational investigations, these complexes are highly stable and superalkali prefer a cubic position of the nanocage energetically to be chemisorbed. When superalkali doped on B[Formula: see text]N[Formula: see text], a significant decrease in the HOMO–LUMO energy gap was observed and this shifted the B[Formula: see text]N[Formula: see text] nanocage from insulator to n-type semiconductor. The HOMO–LUMO energy gap of pure B[Formula: see text]N[Formula: see text] was 6.84[Formula: see text]eV and when superalkali (OLi3) is doped on it, the HOMO–LUMO energy gap was changed in the range of 3.94–0.42[Formula: see text]eV. BNM2b showed a HOMO–LUMO energy gap of 3.94[Formula: see text]eV, while BNM4a showed a minimum HOMO–LUMO energy gap (0.42[Formula: see text]eV). Further, these systems showed a remarkable large first hyperpolarizability ([Formula: see text]) in the range of 626.72–75,757[Formula: see text]au and 1045–12,6261[Formula: see text]au. When the charge was shifted from superalkali to the nanocage, a small change in transition energies has occurred and consequently, hyperpolarizability ([Formula: see text]) values increased significantly. The vertical ionization energy of pure B[Formula: see text]N[Formula: see text] is 7.71[Formula: see text]eV, as superalkali is doped on it showed a significant change in VIE in BNM2b that indicated the highest VIE of about 6.47[Formula: see text]eV and BNM4a indicated lowest VIE 2.51[Formula: see text]eV. The TD-DFT investigations described that complexes illustrated greater transparency in the UV part which involves apart from greater NLO response for practical applications in the area of activity of optoelectronics.

DFT Study of Super Halogen Doped Borophene With Enhanced Nonlinear Optical Properties

The concern of the present study is to investigate the non-linear optical properties of super halogen doped borophene owing to its broad applications. The first principle study of the material for its non-linear optical properties elaborated its use for electrical and optical applications. The super halogen-based borophene in lithium ion-based batteries and medical appliances have made it one of the most potential materials for optoelectronics. First, hyperpolarizability (βo) of pure and doped B36 is computed and the difference between their values was examined. The vertical ionization energy (VIE) was calculated for pure and doped systems. The interaction energy (Eint) for all combinations was computed. It would be expected to one of the best materials to have high capacity and resistance. For all the calculations and to calculate the HOMO and LUMO energy gap, the density functional theory (DFT) method was used. After observing all the above properties, it was predicted that these combinations are more beneficial and displayed the better nonlinear optical (NLO) for electronic devices.

COMPUTATIONAL STUDY OF MOLECULAR STRUCTURES AND ANTIOXIDANT MECHANISM OF OVOTHIOLS

In this paper, the molecular structure and antioxidant activity of ovothiols (OSH) have beenstudied by using four DFT functionals, namely B3LYP, B3PW91, X3LYP, M06 with the basisset of 6-311++G(2df,2p). Two major antioxidant mechanisms, namely, hydrogen atom transfer(HAT) and stepwise electron transfer-proton transfer (SET-PT) have been investigated andapplied on three optimized conformations of ovothiols. Bond dissociation enthalpy (BDE),vertical ionization energy (IE), proton dissociation enthalpy (PDE), chemical potential (μ),chemical hardness (η) and global electrophilicity (ω), have been calculated and discussed in thegas phase.

A DENSITY FUNCTIONAL THEORY STUDY OF ANTIOXIDANT ACTIVITY OF ISOTHIOCYANATES IN BROCCOLI SPROUTS (BRASSICA OLERACEA L.)

Antioxidant activity of 9 isothiocyanate derivatives (−N=C=S) extracted from Broccolisprouts (Brassica oleracea L.) has been investigated using density functional theory (DFT) –based computational methods. Through the hydrogen atom transfer (HAT) and single electrontransfer (SET) mechanisms, three thermodynamic parameters including bond dissociationenthalpy (BDE), vertical ionization energy (IE), and vertical electron affinity (EA) werecalculated in the gas phase using B3LYP/6-311++G(3df,3p)//B3LYP/6-311G(d,p) modelchemistry. As a result, the isothiocyanate (ITC) shows potential antioxidant activity via HATmechanism. The most potential antioxidant is 3-isothiocyanato pro-1-en (3ITCP) withBDE(C−H) of 72.9 kcal/mol. The SET mechanism is not dominant in case of the studied ITCs.Moreover, the radicals formed H• removal had more reactive and less stable than the intialneutral compounds with lower IE, higher EA and ω.

Keto, thione, selone, and tellone carotenoids — Changing antioxidants to antireductants

Heterocarotenoids can be considered as xenobiotic compounds as they are foreign to living organisms. Thione carotenoids are heterocarotenoids that are particularly interesting because the presence of sulfur shifted the absorption to longer wavelengths than the corresponding keto carotenoids. This may be important for further applications such as the development of new pigments. Keto carotenoids are well-known antiradical molecules, however, nothing is known about heterocarotenoids acting as free radical scavengers. Thus, the main goal of this investigation is to study the antiradical properties of some heterocarotenoids, such as thione, selone, and tellone carotenoids. For this purpose, the energy differences between singlets and triplets are used to analyze the singlet oxygen quenching mechanism, and the electron transfer mechanism is investigated, taking into account that these may constitute antiradical molecules either donating or accepting electrons (antioxidants or antireductants). To analyze these mechanisms, vertical ionization energy (I), vertical electron affinity (A), and electrodonating (χ−) and electroaccepting (χ+) electronegativities were evaluated by applying density functional theory calculations. The investigated heterocarotenoids are as effective as keto carotenoids in terms of being either electron donors or acceptors, and therefore, they have a similar capacity for scavenging free radicals. Changing the C=O group to C=S, C=Se, or C=Te converts an antioxidant to an antireductant.

The Ionizations of C60 in the Gas Phase and in Thin Solid Films.

ABSTRACTThe high-resolution He I photoelectron spectrum of C60 in the gas phase is reported and compared with the photoelectron spectrum of C60as a thin film prepared by vapor deposition (one to three monolayers) on gold. The spectra show low valence ionization bands that are very sharp and well-separated for a molecule of this size, consistent with the highly symmetric truncated icosahedral structure and theoretical calculations. The total band widths of the valence ionizations from the thin film samples are comparable to those from the gas phase species, showing that the electronic interactions between the molecules and with the surface do not significantly influence these measurements of the molecular electronic structure. The gas phase photoelectron spectra also show vibrational fine structure in the first and second ionization bands with spacings that are consistent with the two totally symmetric vibrational modes of C60. The first vertical ionization energy relative to the vacuum level is determined to be 7.61 ± 0.02 eV from these gas phase measurements.

Effects of In-Plane π’ Bonding on Electronic Transition Energies for Inorganic Polymers

ABSTRACTThe electronic structure of organic and inorganic polymeric systems are well described in terms of their molecular symmetry, even with the large bond polarity shown by such systems as polyphosphazenes. We have performed calculations using the semi-empirical CNDO/1 method to determine the valence electronic structure for a series of model phosphonitrilic and organic compounds. The optical transition energies for phosphonitrilic compounds are greater than their organic counterparts as a result of in-plane π’ bonding interactions. The extent of these interactions is modulated by the electronegativity of the substituent groups on the phosphorus atoms. We report values for the vertical ionization energy and electronic absorption wavelengths, and use molecular orbital contour analysis to show the effects of ligand electronegativity on the π’ network.