A 6-31G* chemistry of isoelectronic tetrahedral XL4ε and YL4ε (X = Li to F; Y = Na to Cl; L = H, F, Cl) species. Part 2. Energies, bond lengths, and critical radii

1988 ◽  
Vol 66 (9) ◽  
pp. 2465-2475 ◽  
Author(s):  
S. C. Choi ◽  
Russell J. Boyd ◽  
Osvald Knop
Keyword(s):  
Central Atom ◽  
Energy Levels ◽  
Electronic Energy ◽  
Energy Requirements ◽  
Electronic Charge ◽  
Quadratic Polynomials ◽  
Bond Lengths ◽  
Total Electronic Energy ◽  
The Stability ◽  
Net Charges

The 6-31G* ab initio treatment of isoelectronic tetrahedral species now covers the complete XL4ε and YL4ε series (X = Li to F; Y = Na to Cl; L = H, F, Cl). The optimized equilibrium molecular parameters comprise the total electronic energy E, bond lengths, critical radii rc, MO energy levels, net charges, and electron densities at the bond critical points; only the first four are discussed in this part. The stability in terms of E, of the tetrahedral species relative to some competing systems, is examined. The energy requirements associated with the transfer of electronic charge from L to the central atom are reflected in the variation of the critical radii with the oxidation state m of X and Y, with important differences between the first- and the second-row elements. In an appendix it is shown that the E~HF limit energies of isoelectronic He-core (Li+ ff.), Ne-core (Na+ ff.), and Ar-core (K+ ff.) series of ions can be represented analytically by quadratic polynomials in m to an accuracy of ~0.0023% of the E~HF limit range or better, and that these approximations for the three series are qualitatively of the type E = −a(Z − b)2.

Quantum Mechanical Investigation of Geometrical Structure and Dynamic Behavior of h-BNNT (9,9-5) and h-AlNNT (9,9-5)Single-Walled Nanotubes: NBO Analysis

2019 ◽  
Vol 16 (9) ◽  
pp. 705-717
Author(s):  
Mehrnoosh Khaleghian ◽  
Fatemeh Azarakhshi
Keyword(s):  
Carbon Nanotubes ◽  
Density Functional ◽  
Structural Parameters ◽  
Energy Levels ◽  
Nbo Analysis ◽  
Electronic Energy ◽  
Boron Nitride Nanotubes ◽  
Basis Set ◽  
B3lyp Method ◽  
Mechanical Investigation

In the present research, B45H36N45 Born Nitride (9,9) nanotube (BNNT) and Al45H36N45 Aluminum nitride (9,9) nanotube (AlNNT) have been studied, both having the same length of 5 angstroms. The main reason for choosing boron nitride nanotubes is their interesting properties compared with carbon nanotubes. For example, resistance to oxidation at high temperatures, chemical and thermal stability higher rather than carbon nanotubes and conductivity in these nanotubes, unlike carbon nanotubes, does not depend on the type of nanotube chirality. The method used in this study is the density functional theory (DFT) at Becke3, Lee-Yang-Parr (B3LYP) method and 6-31G* basis set for all the calculations. At first, the samples were simulated and then the optimized structure was obtained using Gaussian 09 software. The structural parameters of each nanotube were determined in 5 layers. Frequency calculations in order to extract the thermodynamic parameters and natural bond orbital (NBO) calculations have been performed to evaluate the electron density and electrostatic environment of different layers, energy levels and related parameters, such as ionization energy and electronic energy, bond gap energy and the share of hybrid orbitals of different layers.

scholarly journals The ultra-violet spectrum of magnesium hydride. 1.—The band at λ 2430

1929 ◽  
Vol 122 (790) ◽  
pp. 442-455 ◽  
Keyword(s):  
Fine Structure ◽  
General Structure ◽  
Energy Levels ◽  
Visible Region ◽  
Ultra Violet ◽  
Present Theory ◽  
Magnesium Hydride ◽  
Electronic Energy ◽  
Band Spectra ◽  
Electronic Energy Levels

The system of bands in the visible region of the emission spectrum of magnesium hydride is now well known. The bands with heads at λλ 5622, 5211, 4845 were first measured by Prof. A. Fowler, who arranged many of the strongest lines in empirical series for identification with absorption lines in the spectra of sun-spots. Later, Heurlinger rearranged these series in the now familiar form of P, Q and R branches, and considered them, with the OH group, as typical of doublet systems in his classification of the fine structure of bands. More recently, W. W. Watson and P. Rudnick have remeasured these bands, using the second order of a 21-foot concave grating, and have carried out a further investigation of the fine structure in the light of the present theory of band spectra. Their detection of an isotope effect of the right order of magnitude, considered with the general structure of the system, and the experimental work on the production of the spectrum, seems conclusive in assigning these bands to the diatomic molecule MgH. The ultra-violet spectrum of magnesium hydride is not so well known. The band at λ 2430 and the series of double lines in the region λ 2940 to λ 3100, which were recorded by Prof. Fowler in 1909 as accompanying the group of bands in the visible region, appear to have undergone no further investigation. In view of the important part played by hydride band spectra in the correlation of molecular and atomic electronic energy levels, it was thought that a study of these features might prove of interest in yielding further information on the energy states of the MgH molecule. The present paper deals with observations on the band at λ 2430; details of an investigation of the other features of the ultra-violet spectrum will be given in a later communication.

scholarly journals Determination of Maintenance Energy Requirements for Fattening Castrated Korean Black Goats (Capra hircus coreanae)

Animals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1543
Author(s):  
Sang-Ho Moon ◽  
Yeong Sik Yun ◽  
Na Yeon Kim ◽  
Sanguk Chung ◽  
Qi Man Zhang ◽  
...  
Keyword(s):  
Body Weight ◽  
Energy Intake ◽  
Energy Levels ◽  
Average Daily Gain ◽  
Nutrient Digestibility ◽  
Metabolic Energy ◽  
Energy Requirements ◽  
Capra Hircus ◽  
Maintenance Energy ◽  
Daily Gain

Twelve adult (10 months old) castrated Korean black goats, with an average initial body weight of 24.98 ± 3.7 kg, were used in this experiment to determine their maintenance energy requirements. Dry matter intakes (g/d, p = 0.945) were not affected by energy levels, but metabolic energy intake (kcal/d, p < 0.002) and average daily gain (g/d, p < 0.001) were significantly increased at higher energy levels. Nutrient digestibility was similar in the treatments, but crude fat digestibility increased with the addition of protective fat powder (p = 0.001). The energy required for fattening the castrated Korean black goats was estimated using the correlation between metabolic energy intake per dietary body weight and average daily gain per dietary body weight. The Y-axis intercept value was calculated to be 108.76 kcal/kg BW0.75 (p < 0.05, r2 = 0.6036), which was the metabolic energy requirement for maintaining the lives of the fattening Korean black goats. The estimated energy requirements of the black goat can improve specification techniques, such as the energy level and the amount of feed supply required for domestic black goats.

DFT STUDY OF STRUCTURAL AND ELECTRONIC PROPERTIES OF ENDOHEDRAL COMPLEXES OF GROUP V ATOMS WITH C60

2013 ◽  
Vol 27 (26) ◽  
pp. 1350152 ◽  
Author(s):  
AKSHU PAHUJA ◽  
SUNITA SRIVASTAVA
Keyword(s):  
Electronic Properties ◽  
Energy Gap ◽  
Central Atom ◽  
Energy Levels ◽  
Electronic Configuration ◽  
Group V ◽  
Foreign Atom ◽  
Endohedral Fullerenes ◽  
Endohedral Complexes ◽  
Structural And Electronic Properties

The structural and electronic properties of endohedral fullerenes formed by encapsulation of each of the group V elements inside the buckminsterfullerene cage have been investigated. The calculations reveal that all these species are thermodynamically stable, though the formation of Sb@C 60 and Bi@C 60 is slightly endothermic. The central atom preserves its electronic configuration and the quartet state. The energy gap and energy levels are perturbed by the inclusion of a foreign atom. The band gap of Sb@C 60 and Bi@C 60 is found to be significantly smaller than pristine C 60, suggesting the reactivity of these complexes.

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