Marian Radny | University of Newcastle NSW (original) (raw)
Papers by Marian Radny
The Journal of Physical Chemistry C, 2017
Diboron trioxide (B 2 O 3) assumes critical importance as an effective oxidation inhibitor in pro... more Diboron trioxide (B 2 O 3) assumes critical importance as an effective oxidation inhibitor in prominent chemical applications. For instance, it has been extensively used in electrolysis and ceramic/glass technology. Results are presented of accurate quantum mechanical calculations using the PW1PW hybrid HF/DFT functional of four low-index surfaces of the low-pressure phase of B 2 O 3 : (101), (100), (011) and (001). Bond lengths, bond angles and net Mulliken charges of the surface atoms are analysed in detail. Total and projected density of states as well as surface energies are discussed. Occurrence of tetrahedral BO 4 units on the lowest energy structures of two of these surfaces has been demonstrated for the first time. The corresponding surface orientations incur larger energies in reference to the two orientations featuring only BO 3 units. All of the four investigated lowest energy structures have no dangling bonds, which reasonably relates to the experimentally observed low reactivity of this compound. Findings in this paper pave the way for potential interest in perspective of future studies on the surfaces of amorphous B 2 O 3 , as well as on the hydroxylation of both crystalline and amorphous B 2 O 3 .
Chemical Physics Letters, 2011
A model for the gas phase oxidation of hydrogen chloride in the presence of copper (II) chloride ... more A model for the gas phase oxidation of hydrogen chloride in the presence of copper (II) chloride (the Deacon reaction) has been investigated by the density functional theory. Chlorine (Cl 2) is produced by the thermal decomposition of CuCl 2 generating Cu 2 Cl 2 which reacts with O 2 (3 R g) to form several intermediates and complexes which further react with hydrogen chloride. A key step in the mechanism is the fission of a O-O linkage between two Cu 2 Cl 2 moieties. This step possesses a barrier prohibitive to homogeneous gas phase catalysis but one which is expected to be easily overcome on a copper chloride surface.
Surface Science, 1990
Tbe effect of an image potential on the local surface density of states is investigated in the fr... more Tbe effect of an image potential on the local surface density of states is investigated in the framework of a nearly free electron model by employing the matching Green function method. The influence of the image plane position on the shift and broadening of image induced surface resonance is discussed. Finally, results are compared to experimental data and other theoretical calculations.
Le Journal de Physique Colloques
INTRODUCTION I n o u r previous / I / we have s t u d i e d t h e behaviour of s u r f a c e s t ... more INTRODUCTION I n o u r previous / I / we have s t u d i e d t h e behaviour of s u r f a c e s t a t e s i n t h e presence of adsorbed atoms and we have o b t a i n e d Tamm-like e l e c t r o n l o c a l i z e d a t t h e c r y s t a l s u r f a c e and a d s o r p t i o n -l i k e
A computer-aid, online tutorial/assessment scheme based on an eGrade (Wiley & Sons) software pack... more A computer-aid, online tutorial/assessment scheme based on an eGrade (Wiley & Sons) software package designed and implemented in the introductory physics courses at the University of Newcastle (Australia) is described and evaluated. It is shown that the designed approach enhances student's satisfaction and performance, and represents a valuable experience in developing a consistent tutorial/assessment online supporting scheme for large-class introductory physics courses.
We report on a new laboratory program implemented in the first year, lower-level service physics ... more We report on a new laboratory program implemented in the first year, lower-level service physics course at the University of Newcastle in 2005. It is shown that the new laboratory environment has resulted in very high overall students' satisfaction for the new program and positively influenced the way they look at their laboratory-based learning experience. In particular it is shown that their study approaches have been influenced in a positive manner, with students acknowledging that the new laboratory structure has developed their teamwork skills and helped them to better understand the lecture material and the underlying physical principles.
Surface Science, 1989
The role of a nonuniform electric field in a simplified picture of field ionization at the X gap ... more The role of a nonuniform electric field in a simplified picture of field ionization at the X gap on a Cu(100) surface was studied. The model potential was assumed to be a combination of image, linear (electric field), and imaging gas potentials.
AIP Conference Proceedings, 2000
In this paper we examine how the total energies of finite, open-ended, single-walled carbon nanot... more In this paper we examine how the total energies of finite, open-ended, single-walled carbon nanotubes are affected by the presence of chemically active dangling bonds at the ends of the tubes. Results have been obtained by carrying out empirical Brenner potential ...
Surface Science, Aug 1, 2003
Several models have been proposed in the literature for the initial stages of the dissociative ch... more Several models have been proposed in the literature for the initial stages of the dissociative chemisorption of silane (SiH 4) on the Si(1 1 1)7 × 7 surface. In this paper, geometry optimisation calculations using the extended Brenner empirical potential have been performed to determine which of these models yields the minimum energy structure. The lowest energy configurations are found to correspond to the dissociation of silane into SiH 2 and two hydrogen atoms. The minimum energy structure involves the adsorption of the two hydrogen atoms onto the dangling bonds of an adjacent adatom and rest atom, and the insertion of the remaining SiH 2 fragment into one of the adatom backbonds. These results are discussed in the light of the existing experimental data.
Materials Transactions, 2007
ABSTRACT
Carbon, May 1, 2005
... also predicts a quadratic relationship between the radius of a SWCNT and the external radius ... more ... also predicts a quadratic relationship between the radius of a SWCNT and the external radius of the circular torus that is formed by bending this nanotube and joining its ends [4]. It thus follows that the thinner the initial tube, the smaller the defect-free circular toroid that can be ...
Physica B+C
The effects of oxidation on the Tamm-and adsorption-like surface states of a semi-infinite 8-well... more The effects of oxidation on the Tamm-and adsorption-like surface states of a semi-infinite 8-well model of silicon are studied. In particular, the behaviour of these states as an oxygen atom approaches the surface is analyzed. It is found that there are ranges of the distance d between the oxygen atom and the crystal surface for which two states can exist o simultaneously; for d ~< 3 A there exist no surface states in the forbidden energy gap. The localization properties of electrons in both types of states are discussed with the help of the relative probability density function.
Journal of Physics Condensed Matter
ABSTRACT
Physical Review B
ABSTRACT
Materials transactions
ABSTRACT
Surface Science, 2011
The adsorption of lead (Pb) atoms on the clean Si(001)c(4 × 2) reconstructed surface as a functio... more The adsorption of lead (Pb) atoms on the clean Si(001)c(4 × 2) reconstructed surface as a function of the adatom coverage is investigated using density functional theory. It is shown that the growth of Pb adatom chains from the most stable monomer configuration, the end-dimer-bridge configuration, proceeds via the formation of inter-and intra-row ad-dimers, and ad-trimers. The calculated energetics of long Pb chains show that the most thermodynamically stable chains are composed exclusively of inter-row dimers, and that monomer termination of these chains is favoured over termination by a dimer.
Surface Science, 1997
Ab initio Hartree Fock DFT cluster calculations have been performed of the interaction of hydroge... more Ab initio Hartree Fock DFT cluster calculations have been performed of the interaction of hydrogen with the Si(1 ll)7 x 7 surface. These calculations have enabled the determination of the various equilibrium structures which result when up to five hydrogen atoms are allowed to adsorb near the adatom and rest atom sites of the Si( 111 )7 x 7 surface. As progressively more hydrogen atoms are chemisorbed near an adatom site, each hydrogen-bonded adatom is found to move from its original three-fold (T4) site (one hydrogen atom) to an adjacent bridge site (two and three hydrogen atoms), and then on-top of a neighbouring first layer silicon atom (more than three hydrogen atoms). The lowest calculated adatom desorption energy is found to be 2.40 eV and corresponds to the desorption of Sill 2 from above a neighbouring first layer silicon atom. In contrast to an adatom, a hydrogenbonded rest atom is found to remain close to its original three-fold equilibrium position. The smallest rest atom desorption energy is 2.10 eV and corresponds to an Sill3 surface complex. ~ 1997 Elsevier Science B.V.
Physical Review B, 1986
... J. M. Blatt and V. F. %'eisskopf, Theoretical Nuclear Ihysies (Wiley, New York, 1952). i... more ... J. M. Blatt and V. F. %'eisskopf, Theoretical Nuclear Ihysies (Wiley, New York, 1952). iJ. L. Powell and B. Crasemann, Quantum Mechanics (Addison-%'esley, New York, 1961). 3E. ... M. Steslickaand K. F. %'ojciechowski, Physica 32, 1274 (1966). 9%'. Shockley, Phys. Rev. ...
The Journal of Physical Chemistry C, 2017
Diboron trioxide (B 2 O 3) assumes critical importance as an effective oxidation inhibitor in pro... more Diboron trioxide (B 2 O 3) assumes critical importance as an effective oxidation inhibitor in prominent chemical applications. For instance, it has been extensively used in electrolysis and ceramic/glass technology. Results are presented of accurate quantum mechanical calculations using the PW1PW hybrid HF/DFT functional of four low-index surfaces of the low-pressure phase of B 2 O 3 : (101), (100), (011) and (001). Bond lengths, bond angles and net Mulliken charges of the surface atoms are analysed in detail. Total and projected density of states as well as surface energies are discussed. Occurrence of tetrahedral BO 4 units on the lowest energy structures of two of these surfaces has been demonstrated for the first time. The corresponding surface orientations incur larger energies in reference to the two orientations featuring only BO 3 units. All of the four investigated lowest energy structures have no dangling bonds, which reasonably relates to the experimentally observed low reactivity of this compound. Findings in this paper pave the way for potential interest in perspective of future studies on the surfaces of amorphous B 2 O 3 , as well as on the hydroxylation of both crystalline and amorphous B 2 O 3 .
Chemical Physics Letters, 2011
A model for the gas phase oxidation of hydrogen chloride in the presence of copper (II) chloride ... more A model for the gas phase oxidation of hydrogen chloride in the presence of copper (II) chloride (the Deacon reaction) has been investigated by the density functional theory. Chlorine (Cl 2) is produced by the thermal decomposition of CuCl 2 generating Cu 2 Cl 2 which reacts with O 2 (3 R g) to form several intermediates and complexes which further react with hydrogen chloride. A key step in the mechanism is the fission of a O-O linkage between two Cu 2 Cl 2 moieties. This step possesses a barrier prohibitive to homogeneous gas phase catalysis but one which is expected to be easily overcome on a copper chloride surface.
Surface Science, 1990
Tbe effect of an image potential on the local surface density of states is investigated in the fr... more Tbe effect of an image potential on the local surface density of states is investigated in the framework of a nearly free electron model by employing the matching Green function method. The influence of the image plane position on the shift and broadening of image induced surface resonance is discussed. Finally, results are compared to experimental data and other theoretical calculations.
Le Journal de Physique Colloques
INTRODUCTION I n o u r previous / I / we have s t u d i e d t h e behaviour of s u r f a c e s t ... more INTRODUCTION I n o u r previous / I / we have s t u d i e d t h e behaviour of s u r f a c e s t a t e s i n t h e presence of adsorbed atoms and we have o b t a i n e d Tamm-like e l e c t r o n l o c a l i z e d a t t h e c r y s t a l s u r f a c e and a d s o r p t i o n -l i k e
A computer-aid, online tutorial/assessment scheme based on an eGrade (Wiley & Sons) software pack... more A computer-aid, online tutorial/assessment scheme based on an eGrade (Wiley & Sons) software package designed and implemented in the introductory physics courses at the University of Newcastle (Australia) is described and evaluated. It is shown that the designed approach enhances student's satisfaction and performance, and represents a valuable experience in developing a consistent tutorial/assessment online supporting scheme for large-class introductory physics courses.
We report on a new laboratory program implemented in the first year, lower-level service physics ... more We report on a new laboratory program implemented in the first year, lower-level service physics course at the University of Newcastle in 2005. It is shown that the new laboratory environment has resulted in very high overall students' satisfaction for the new program and positively influenced the way they look at their laboratory-based learning experience. In particular it is shown that their study approaches have been influenced in a positive manner, with students acknowledging that the new laboratory structure has developed their teamwork skills and helped them to better understand the lecture material and the underlying physical principles.
Surface Science, 1989
The role of a nonuniform electric field in a simplified picture of field ionization at the X gap ... more The role of a nonuniform electric field in a simplified picture of field ionization at the X gap on a Cu(100) surface was studied. The model potential was assumed to be a combination of image, linear (electric field), and imaging gas potentials.
AIP Conference Proceedings, 2000
In this paper we examine how the total energies of finite, open-ended, single-walled carbon nanot... more In this paper we examine how the total energies of finite, open-ended, single-walled carbon nanotubes are affected by the presence of chemically active dangling bonds at the ends of the tubes. Results have been obtained by carrying out empirical Brenner potential ...
Surface Science, Aug 1, 2003
Several models have been proposed in the literature for the initial stages of the dissociative ch... more Several models have been proposed in the literature for the initial stages of the dissociative chemisorption of silane (SiH 4) on the Si(1 1 1)7 × 7 surface. In this paper, geometry optimisation calculations using the extended Brenner empirical potential have been performed to determine which of these models yields the minimum energy structure. The lowest energy configurations are found to correspond to the dissociation of silane into SiH 2 and two hydrogen atoms. The minimum energy structure involves the adsorption of the two hydrogen atoms onto the dangling bonds of an adjacent adatom and rest atom, and the insertion of the remaining SiH 2 fragment into one of the adatom backbonds. These results are discussed in the light of the existing experimental data.
Materials Transactions, 2007
ABSTRACT
Carbon, May 1, 2005
... also predicts a quadratic relationship between the radius of a SWCNT and the external radius ... more ... also predicts a quadratic relationship between the radius of a SWCNT and the external radius of the circular torus that is formed by bending this nanotube and joining its ends [4]. It thus follows that the thinner the initial tube, the smaller the defect-free circular toroid that can be ...
Physica B+C
The effects of oxidation on the Tamm-and adsorption-like surface states of a semi-infinite 8-well... more The effects of oxidation on the Tamm-and adsorption-like surface states of a semi-infinite 8-well model of silicon are studied. In particular, the behaviour of these states as an oxygen atom approaches the surface is analyzed. It is found that there are ranges of the distance d between the oxygen atom and the crystal surface for which two states can exist o simultaneously; for d ~< 3 A there exist no surface states in the forbidden energy gap. The localization properties of electrons in both types of states are discussed with the help of the relative probability density function.
Journal of Physics Condensed Matter
ABSTRACT
Physical Review B
ABSTRACT
Materials transactions
ABSTRACT
Surface Science, 2011
The adsorption of lead (Pb) atoms on the clean Si(001)c(4 × 2) reconstructed surface as a functio... more The adsorption of lead (Pb) atoms on the clean Si(001)c(4 × 2) reconstructed surface as a function of the adatom coverage is investigated using density functional theory. It is shown that the growth of Pb adatom chains from the most stable monomer configuration, the end-dimer-bridge configuration, proceeds via the formation of inter-and intra-row ad-dimers, and ad-trimers. The calculated energetics of long Pb chains show that the most thermodynamically stable chains are composed exclusively of inter-row dimers, and that monomer termination of these chains is favoured over termination by a dimer.
Surface Science, 1997
Ab initio Hartree Fock DFT cluster calculations have been performed of the interaction of hydroge... more Ab initio Hartree Fock DFT cluster calculations have been performed of the interaction of hydrogen with the Si(1 ll)7 x 7 surface. These calculations have enabled the determination of the various equilibrium structures which result when up to five hydrogen atoms are allowed to adsorb near the adatom and rest atom sites of the Si( 111 )7 x 7 surface. As progressively more hydrogen atoms are chemisorbed near an adatom site, each hydrogen-bonded adatom is found to move from its original three-fold (T4) site (one hydrogen atom) to an adjacent bridge site (two and three hydrogen atoms), and then on-top of a neighbouring first layer silicon atom (more than three hydrogen atoms). The lowest calculated adatom desorption energy is found to be 2.40 eV and corresponds to the desorption of Sill 2 from above a neighbouring first layer silicon atom. In contrast to an adatom, a hydrogenbonded rest atom is found to remain close to its original three-fold equilibrium position. The smallest rest atom desorption energy is 2.10 eV and corresponds to an Sill3 surface complex. ~ 1997 Elsevier Science B.V.
Physical Review B, 1986
... J. M. Blatt and V. F. %'eisskopf, Theoretical Nuclear Ihysies (Wiley, New York, 1952). i... more ... J. M. Blatt and V. F. %'eisskopf, Theoretical Nuclear Ihysies (Wiley, New York, 1952). iJ. L. Powell and B. Crasemann, Quantum Mechanics (Addison-%'esley, New York, 1961). 3E. ... M. Steslickaand K. F. %'ojciechowski, Physica 32, 1274 (1966). 9%'. Shockley, Phys. Rev. ...