The electronic structure and properties of FeS2 with the space groups of Pa3 and P1 were studied by the density functional theory. The generalized-gradient approximation exchange-correlation functional was used in con...The electronic structure and properties of FeS2 with the space groups of Pa3 and P1 were studied by the density functional theory. The generalized-gradient approximation exchange-correlation functional was used in conjunction with a plane wave-ultrasoft pseudopotential representation. Calculation results show that differences are observed in electronic structures and properties between Pa3 and P1 crystals. The band gap and energy loss of P1 are smaller than those of Pa3 crystal, while the dielectric constant, conductivity, refractive index, extinction coefficient, and intensity of optical absorption of P1 are larger than those of Pa3. These behaviors are attributed to the differences in symmetry, atomic arrangement, and Mulliken bond population of each unit for Pa3 and P1 crystals.展开更多
The incorporation of B element into π-conjugated system is an efficient strategy to tune the steric and electronic structure and thus optoelectronic properties of π-electron systems.The vacant p orbital on the trico...The incorporation of B element into π-conjugated system is an efficient strategy to tune the steric and electronic structure and thus optoelectronic properties of π-electron systems.The vacant p orbital on the tricoordinate B center makes it exhibit several electronic and steric features,such as electron-accepting ability through p-π~＊ conjugation,the high Lewis acidity to coordinate with Lewis bases,as well as the steric bulk arising from the aryl substituent on the B center to get enough kinetic stability.As a result,the boryl group is a very unique electron acceptor.When an electron-donating amino group is present,the triarylboranes would display intense intramolecular charge transfer transitions,which lead to interesting optoelectronic properties and great utilities.This short review summarizes the recent progress in π-electron systems,which contain both B and N elements and thus display intramolecular charge-transfer transitions.The triarylboranes are introduced based on their structural features,including the linear π-system with boryl and amino groups at the terminal positions,the lateral borylsubstituted π-system with amino groups at the terminal positions,the biphenyl π-system with an amino and a boryl groups at o,o＇-positions,nonconjugated U- and V-shaped π-system,macrocylcic π-system with B and N embedded in the ring,B,N-bridged ladder-type π-system,as well as the polycyclicπ-system with B embedded in the center.展开更多
基金financially supported by the Program for New Century Excellent Talents in Universities of China (No. NCET-11-0925)the National Natural Science Foundation of China (No. 51164001)the Scientific Research Foundation of Guangxi University (No.XBZ100498)
文摘The electronic structure and properties of FeS2 with the space groups of Pa3 and P1 were studied by the density functional theory. The generalized-gradient approximation exchange-correlation functional was used in conjunction with a plane wave-ultrasoft pseudopotential representation. Calculation results show that differences are observed in electronic structures and properties between Pa3 and P1 crystals. The band gap and energy loss of P1 are smaller than those of Pa3 crystal, while the dielectric constant, conductivity, refractive index, extinction coefficient, and intensity of optical absorption of P1 are larger than those of Pa3. These behaviors are attributed to the differences in symmetry, atomic arrangement, and Mulliken bond population of each unit for Pa3 and P1 crystals.
基金supported by the Major State Basic Research Development Program of China(No.2007CB613301)the National Natural Science Foundation of China(Nos.50842028 and 50972012)
基金the National Natural Science Foundation of China(Nos.21072117,21272141,21572120)for financial support
文摘The incorporation of B element into π-conjugated system is an efficient strategy to tune the steric and electronic structure and thus optoelectronic properties of π-electron systems.The vacant p orbital on the tricoordinate B center makes it exhibit several electronic and steric features,such as electron-accepting ability through p-π~＊ conjugation,the high Lewis acidity to coordinate with Lewis bases,as well as the steric bulk arising from the aryl substituent on the B center to get enough kinetic stability.As a result,the boryl group is a very unique electron acceptor.When an electron-donating amino group is present,the triarylboranes would display intense intramolecular charge transfer transitions,which lead to interesting optoelectronic properties and great utilities.This short review summarizes the recent progress in π-electron systems,which contain both B and N elements and thus display intramolecular charge-transfer transitions.The triarylboranes are introduced based on their structural features,including the linear π-system with boryl and amino groups at the terminal positions,the lateral borylsubstituted π-system with amino groups at the terminal positions,the biphenyl π-system with an amino and a boryl groups at o,o＇-positions,nonconjugated U- and V-shaped π-system,macrocylcic π-system with B and N embedded in the ring,B,N-bridged ladder-type π-system,as well as the polycyclicπ-system with B embedded in the center.
