DFT Calculations of the Ionization Potential and Electron Affinity of Alaninamide

Adiabatic and vertical ionization potentials （IPs） mad valence electron affmities （EAs） of alaninamide in gas phase have been detennined using density functional theory （BLYP, B3LYP, B3P86） methods with 6-311＋＋G（d, p） basis set, respectively. IPs and EAs of alaninamide in solutions have been calculated at the B3LYP/6-311＋＋G（d, p） level. Five possible conformers of alaninamide and their charged states have been optimized employing density functional theory B3LYP method with 6-311＋＋（d, p） basis set, respectively.

Fragmentation Behavior and Ionization Potentials of Lead Clusters Pb_n(n≤30)

The properties of Pbn（n=2―30） clusters including binding energies,second differences in energy,and HOMO-LUMO gaps,especially fragmentation energies and ionization potentials,have been studied by ab initio calculation.The main fragmentation products of Pbn＋ are shown to be Pb＋Pbn-1＋ for n≤14 and two small cluster fragments for larger ones with n14.The Pb13＋ appears frequently as the products in the fragmentations of large clusters.Also,the calculated ionization potentials of the clusters are consistent with the experiment data.

Ionization Potentials and Electron Affinities of Cu_n Atomic Clusters

Ionization potentials and electron affinities of Cux (n = 2-7) atomic clusters with the optimal geom etries have been calculated by use of SC F-Xa-SW method and Slater's transition state theory. Theo retical calcuIations show that the ionization potentiaIs and electron affinities of Cu. (n = 2-7) atom ic clusters have a sharp even / odd alternation with increasing their sizes, which are related to the electronic structure of Cun atomic clusters. The theoretical results are consistent with the related ex perimental ones.

PSEUDO πIONIZATION POTENTIALS OF H-(CH_2)_n-X

By means of the energy level formula E(p)=α+2βcos(pπ/(n+t+1)). the pseudo π ionization potentials of H-(CH_2)_n-X (X=H, F, Cl, Br, I, OH, and SH) are identified by optimizing linear regression analysis, from which α=13.54±0.50eV and β=1.75±0.13eV are obtained.

THE ELECTRONIC STRUCTURE AND THE IONIZATION POTENTIALS OF Ag_n AND Au_n(n=2,3,4)

The electronic structure of Ag_n and Au_n(n=2,3,4) calculated by DV—X_α method, are different each other, and the ionization potentials of Ag_n and Au_n as a function of cluster size n exhibit an interesting 'saw—tooth' behavior. The interactions between atom Ag—Ag and Au —Au in Ag_2, Au_2 for different bond length are analyzed. The DOS of the orbitals shows those interactions directly.

Fragmentation Behavior and Ionization Potentials of Aluminum Clusters Al_n(n≤40)

Al2-Al40 clusters were studied by means of the all-electron DFT method. The properties of the aluminum clusters including binding energy, the second difference in energy, HOMO-LUMO gap, especially fragmentation energies and ionization potentials, were analyzed. The main products from the dissociations of aluminum cluster ions are shown to be Al ＋ Al^＋n-1 for the larger clusters, and Al^＋ ＋Aln-1 for the smaller ones. And, the calculated ionization potentials are consistent with the experiment data.

Further Investigation on the Correlation between Ionization Potential and Superconductivity of Oxides

The relations of oxygen content, critical temperature TC and mean ionization potential < U0> of superconducting oxides are reported. We found that in oxides oxygen is the major element which governs their < U0> te values and thus oxygen content plays an jmportant role in their superconducting properties. As for Y(123)- and T1-systems oxygenation may improve their TC values, but for Biand Hg-systems oxygenation process is not so important. In Y(123), as the oxygen content increase results in the increase of TC upon < U0>to, while the substitution of Ba2+ by Sr2+ causes the decrease of TC upon < U0 >. These results may provide some clues about the superconductivity of oxides and support further that < Uo > is really a good criterion for oxide superconductivity. Two kinds of possible superconducting oxides are predicted in this paper according to the mean ionization potential criterion.

Photoelectron angular distributions of H ionization in low energy regime:Comparison between different potentials

We theoretically investigate the low energy part of the photoelectron spectra in the tunneling ionization regime by numerically solving the time-dependent Schrdinger equation for different atomic potentials at various wavelengths.We find that the shift of the first above-threshold ionization（ATI） peak is closely related to the interferences between electron wave packets,which are controlled by the laser field and largely independent of the potential.By gradually changing the short-range potential to the long-range Coulomb potential,we show that the long-range potential＇s effect is mainly to focus the electrons along the laser＇s polarization and to generate the spider structure by enhancing the rescattering process with the parent ion.In addition,we find that the intermediate transitions and the Rydberg states have important influences on the number and the shape of the lobes near the threshold.

DFT Studies on the Antiradical Potential of Phenolic Compounds

Phenolic compounds are a class of hazardous substances for human.To study the antiradical potential of a series of phenolic compounds from the aspect of position and substituent type,phenol,o⁃dihydroxybenzene(ODB),m⁃dihydroxybenzene(MDB),p⁃dihydroxybenzene(PDB),paranitrophenol(PNP),and o⁃chlorophenol(OCP)were selected as typical targets.In addition,to elucidate the degradation discrepancy of phenolic compounds,quantum chemical calculations(QCCs)were obtained using the B3LYP method along with a 6-311G(d,p)basis set.Calculations indicate that phenol,ODB,MDB,and PDB,with electron⁃donating groups,exhibited high antiradical potential,while PNP and OCP,with electron⁃withdrawing groups,exhibited low antiradical potential.The chemical indices calculations show that para⁃compounds and ortho⁃compounds had high antiradical ability.Moreover,phenol,ODB,MDB,and PDB possessed higher bond dissociation enthalpy(BDE)and lower adiabatic ionization potential(AIP)values compared with those of OCP and PNP.Medium effects,even in vacuo,were also taken into account to reveal the antiradical ability of phenolic compounds.

Ab initio calculations of the ionization spectrum of SO_2

The ionization spectrum of sulfur dioxide has been successfully studied by using the symmetry-adapted-cluster configuration-interaction （SAC-CI） general-R and SD-R methods and the basis set correlation-consistent polarized valence triple-zeta （cc-pVTZ）. The SAC-CI general-R method reproduces the experimental spectrum well for both the main peaks and the satellite peaks of ionization spectrum of SO2. The sequence of ionic states corresponding to main peaks of SO2 has been re-determined according to the SAC-CI conclusions and it is reordered as X^2A1, A^2B2, B2A2, C^2B1,D^2A1, E^2B2 and F^2A1. Besides, the equilibrium structures and adiabatic ionization potentials （AIPs） of ionic states of main peaks of SO2 are calculated by using the SAC-CI SD-R method.

Ionization in an intense field considering Coulomb correction

We derive a simple ionization rate formula for the ground state of a hydrogen atom in the velocity gauge under the conditions：ω〈〈1 a.u.（a.u.is short for atomic unit） and γ〈〈1（ω is the laser frequency and y is the Keldysh parameter）.Comparisons are made among the different versions of the Keldysh-Faisal-Reiss（KFR） theory.The numerical study shows that with considering the quasi-classical（WKB） Coulomb correction in the final state of the ionized electron,the photoionization rate is enhanced compared with without considering the Coulomb correction,and the Reiss theory with the WKB Coulomb correction gives the correct result in the tunneling regime.Our concise formula of the ionization rate may provide an insight into the ionization mechanism for the ground state of a hydrogen atom.

Structure and stability of neutral and cationic AlnO clusters

In this paper various structural possibilities for AlnO neutral and cationic isomers were investigated by using the B3LYP/6-311G（3df） method. Calculations of this paper predicted the existence of a number of previously unknown isomers. The stabilities of the AlnO （n = 2 - 7） clusters with even n are greater than those with odd n, however the stabilities Of cationic ions have the opposite odd-even alternation. The mass spectra observations of Al17O^＋ and Al19O^＋ ions support our theoretical predictions on their stabilities.

Study of Structures and Electronic Properties of Pd_(n–1)Pb and Pd_n (n≤8) Clusters

Geometric and electronic properties of Pdn–1Pb and Pdn （n≤8） clusters have been studied by using density functional theory with effective core potentials, focusing on the differences between mono- and bimetallic clusters. The average bond length of Pdn–1Pb （n≤8） bimetallic clusters is longer than that of pure palladium clusters except for n = 2 and 3. The most stable structure of Pdn–1Pb （n≤7） is the singlet where there is at least a Pd or Pb atom on its excited state. The energy gaps of Pd–Pb binary clusters are narrower than those of Pdn clusters, and then the chemical activity is strengthened when Pdn clusters are doped with Pb.

Structure and Properties of Semiconductor Microclusters Ga_nP_n(n=1-4): A First Principle Study

The possible geometrical structures and relative stabilities of semiconductor microclusters Ga\-\%n\%P\-\%n(n\%=1\_4) were studied by virtue of density functional calculations with generalized gradient approximation(B3LYP). For the most stable isomers of Ga\-\%n\%P\-\%n(n\%=1\_4) clusters, the electronic structure, vibrational properties, dipole moment, polarizability and ionization potential were analyzed by means of HF, MP2, CISD and B3LYP methods with different basis sets.

Theoretical Calculations on Amphoteric Adsorptions of the Hydrogenated C(100)-2×1 Surface

In this work we study the adsorptions of some small molecules or group on the hydrogenated C（100）-2×1 surface using density functional theory method. The calculated results show that the ionization potential （IP） of the hydrogenated C（100）-2×1 surfaces after adsorption has amphoteric characteristics. From the weak basic NH3 molecule with small IP and negative electron affinity （EA）, through the neutral H2O molecule, to the weak acid HF molecule and the OH group with large EA and IP, the IP values of the adsorbed diamond surfaces vary from decrease, through invariability, to slight increase for HF and obvious increase for OH. In all adsorption species, only the OH group makes the hydrogenated C（100）-2×1 surface change to the metal from the semiconductor with a wide-band gap, while the others only introduce impurity states into the electronic structures of the hydrogenated C（100）-2×1 surfaces.

INFLUENCE OF LANTHANUM STEARATE AND CALCIUM/ZINC STABILIZERS ON STABILIZATION EFFICIENCY OF DIBUTYLTIN DILAURATE TO POLYVINYL CHLORIDE

Influences of lanthanum stearate （LaSt3） and calcium stearate/zinc stearate （Ca/Zn） stabilizers on stabilization efficiency of dibutyltin dilaurate （DBTDL） to polyvinyl chloride （PVC） in air were investigated. The results revealed that the stabilization effect of DBTDL could be achieved by the La/Sn stabilizers with a ratio of 8/2. Addition of DBTDL could enhance thermal property and reduce dynamic storage modulus （G＇） at 180℃ for PVC containing LaSt3 or Ca/Zn stabilizers. On the other hand, incorporation of LaSh did not influence the stabilization efficiency of DBTDL markedly; while addition of Ca/Zn stabilizers could significantly decrease thermal property for the DBTDL stabilized PVC. Furthermore, the effects of LaSt3 and Ca/Zn stabilizers on the stabilization efficiency of DBTDL were explained in the framework of ionization potential.

Theoretical Study on the Antioxidant Activity of Curcumin

The computational results for curcumin at the B3LYP/6-31G(d,p) level show that the enol form of curcumin is more stable than the diketo form because of an intramolecular hydrogen bond, which extends the conjugation effect in the enol chain, formed in the enol structure. Cis-diketone form can not be obtained, presumably due to the strong repulsion between the carbonyl dipoles aligned in parallel. According to the phenolic O—H bond dissociation en- thalpy, curcumin in its most stable form can be suggested to be a relatively good antioxidant. In order to avoid overcoming H-bond interaction and to improve the antioxidant activity of curcumin, a catechol moiety was incor- porated into curcumin for designing a novel antioxidant. It is found that the designed molecule is much more effi- cient to scavenge radical than curcumin, comparable to vitamin E. Moreover, the ionization potential of the de- signed molecule is similar to that of curcumin, indicating that the designed molecule can not display the prooxidant effect.

Theoretical Analysis on Magnetic Properties of Conjugated Organic Molecules Containing Borepin

Theoretical study about the magnetic properties of conjugated organic molecules containing borepin with π current density was carried out. 1-（2,4,6-Trimethylphenyl）borepin moiety is the center and other different groups are situated on the both fl sides, which are named molecules 1--12 as theoretical model in order to establish the rela- tionship between aromaticity and geometry variation of borepin. The optimized molecular structures of molecules 1--12 are almost keeping planar and the C2--C3 bond length of borepin turns longer from molecule 1 to molecule 12 Different borepin-annulated ring could change the conjugated effect of π-electron between borepin and these bore- pin-annulated rings. Moreover, the molecule presents antiaromaticity, in other words, the molecule became unstable when the C2--C3 bond length of borepin extended more than ca. O. 1417 nm. But the fl position fragment and substi- tuent groups of borepin are not affected in this case, they are still steady. However, the central borepin ring current is counteracted by symmetrical overlap of it with affiliated borepin-annulated ring current. Hence, the central borepin ring breaking would be liable to occur. These molecules have higher vertical ionization potentials（VIPs） and lower vertical electron affinities（VEAs）, which suggests that these molecules could easily exist in anionic form.