ORCID Profile
0000-0002-4406-0430
Current Organisation
University of Adelaide
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Publisher: Elsevier BV
Date: 07-1982
Publisher: Elsevier BV
Date: 09-1986
Publisher: Elsevier BV
Date: 12-1997
Publisher: CSIRO Publishing
Date: 1997
DOI: 10.1071/P96073
Abstract: Recent experiments, carried out in highly pure s les of molecular nitrogen, have demonstrated the strong influence exerted by neutral, excited metastable states. The influence of the electronically excited, metastable N2(A) state on the ionisation growth is demonstrated through observation of the diffusion phenomena associated with the spatial and temporal growth of ionisation. Evidence has also emerged demonstrating the existence of a second metastable particle influence. The diffusion time observed, however, is not consistent with it being due entirely to an electronically excited state such as the metastable N2(a′) state. Rather the observations suggest the possibility that intersystem crossings between the N2(a′), the highly vibrationally excited N2(X) states and the N2(A) state may be responsible for the increased diffusion time and large molecular size. The possible relevance of these findings to applications such as plasma nitriding is canvassed.
Publisher: CSIRO Publishing
Date: 1997
DOI: 10.1071/P96071
Abstract: Ongoing work aimed at developing highly efficient methods of populating a chosen sublevel of an energy level highlights the need to understand off-resonant effects in coherent excitation. This motivated us to re-examine some aspects of the theory of coherent excitation in a three-state system with a view to obtaining algebraic expressions for off-resonant eigenvalues and eigenvectors. Earlier work gives simple closed-form expressions for the eigenvalues this system, expressions applying even when the system is not on two-photon resonance. We present here expressions of similar simplicity for the components of the normalised eigenvectors. The analytic properties of these components explain the observed sensitivity of the stimulated-Raman-adiabatic-passage process (STIRAP) to the condition of two-photon resonance. None of the eigenstates is ‘trapped’ or ‘dark’ unless the system is on two-photon resonance off resonance, all states have nonzero projections on the unperturbed intermediate state. A simple argument shows that no dressed state can be adiabatically connected to both the unperturbed initial and final states when the system is off two-photon resonance. That is, adiabatic transfer from initial to final state requires that these be degenerate before and after the STIRAP pulse sequence, and this implies zero two-photon detuning. However, substantial transfer probabilities are observed experimentally for very small two-photon detunings. We show that such systems are characterised by very sharp avoided crossings of two eigenvalues, and that the observed population transfer can be understood as an effect of non adiabatic transitions occurring at the avoided crossings.
Publisher: Elsevier BV
Date: 06-1981
Publisher: American Physical Society (APS)
Date: 03-1989
Publisher: American Physical Society (APS)
Date: 08-1986
Publisher: Elsevier BV
Date: 1986
Publisher: Elsevier BV
Date: 09-1985
Publisher: American Physical Society (APS)
Date: 05-1984
Publisher: American Physical Society (APS)
Date: 1988
Publisher: American Physical Society (APS)
Date: 03-1985
Publisher: Elsevier BV
Date: 07-1978
Publisher: Elsevier BV
Date: 05-1999
Publisher: The Optical Society
Date: 20-03-2019
DOI: 10.1364/AO.58.002408
Publisher: Elsevier BV
Date: 2000
Publisher: Elsevier BV
Date: 08-1980
Publisher: Elsevier BV
Date: 1998
Publisher: American Physical Society (APS)
Date: 12-11-1979
Publisher: Elsevier BV
Date: 06-1979
Publisher: American Physical Society (APS)
Date: 03-1985
Publisher: Elsevier BV
Date: 1988
Publisher: IEEE
Date: 05-2010
Publisher: IOP Publishing
Date: 07-1997
DOI: 10.1143/JJAP.36.4941
Abstract: This study compares the nitriding efficiency of a low-pressure pure-nitrogen rf plasma for the materials AISI-316 stainless steel, 99.8% iron and the low-alloy steels AISI 4140 and En41B. The process temperature was 400° C a range of gas pressures and biasing conditions was explored. The treated s les were examined using instrumented microhardness measurements, proton backscattering, X-ray diffraction and other diagnostics. The degree of nitriding is enhanced by increased bombardment by excited neutral molecules. Ion bombardment assists in the nitriding of iron and the low-alloy steels studied, apparently by aiding the production of Fe 2-3 N. This phase does not form in the nitriding of 316 stainless steel, and therefore treatment of this material is not assisted by ion bombardment. In comparing low-pressure rf plasmas to procedures involving higher pressures and temperatures, the process described here is more appropriate for hardening austenitic stainless steel, but perhaps less appropriate for the other materials.
Publisher: Elsevier BV
Date: 08-1984
Publisher: Elsevier BV
Date: 04-1984
Publisher: American Physical Society (APS)
Date: 11-04-1977
Publisher: IOP Publishing
Date: 02-1977
Publisher: Elsevier BV
Date: 05-1996
Publisher: Elsevier BV
Date: 08-1980
Publisher: Elsevier BV
Date: 08-2001
Publisher: Elsevier BV
Date: 07-1985
Publisher: Elsevier BV
Date: 05-1999
Publisher: Elsevier BV
Date: 09-2005
Publisher: Elsevier BV
Date: 08-1987
Publisher: Elsevier BV
Date: 02-2007
Publisher: Elsevier BV
Date: 12-1977
Publisher: American Physical Society (APS)
Date: 11-1984
Publisher: Elsevier BV
Date: 06-1987
Publisher: IOP Publishing
Date: 21-06-1997
Publisher: Elsevier BV
Date: 04-1979
Publisher: Elsevier BV
Date: 08-1988
Publisher: IOP Publishing
Date: 14-12-1994
Publisher: Elsevier BV
Date: 10-1992
Publisher: Elsevier BV
Date: 06-1983
Publisher: Elsevier BV
Date: 2003
Publisher: Military Operations Research Society
Date: 12-2008
DOI: 10.5711/MORJ.13.1.5
Publisher: American Physical Society (APS)
Date: 11-03-1985
Publisher: Elsevier BV
Date: 12-1983
Publisher: American Physical Society (APS)
Date: 03-1986
Publisher: American Physical Society (APS)
Date: 07-1995
Publisher: IOP Publishing
Date: 14-07-1993
Publisher: Elsevier BV
Date: 11-1994
Publisher: Elsevier BV
Date: 06-1988
Publisher: Elsevier BV
Date: 12-1977
Publisher: American Physical Society (APS)
Date: 02-1987
Publisher: Elsevier BV
Date: 05-1996
Publisher: American Physical Society (APS)
Date: 08-12-1980
Publisher: Elsevier BV
Date: 03-1989
No related grants have been discovered for Matthew Peter Fewell.