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Articles 31501 - 31530 of 34554

Full-Text Articles in Physical Sciences and Mathematics

Reversibility Of Ct And Mr Findings In Neuro-Behçet Disease, Dushyant V. Patel, Michael J. Neuman, Daniel B. Hier Jan 1989

Reversibility Of Ct And Mr Findings In Neuro-Behçet Disease, Dushyant V. Patel, Michael J. Neuman, Daniel B. Hier

Chemistry Faculty Research & Creative Works

A Woman with Neuro-Behçet Disease Characterized by Recurrent Attacks of Meningoencephalitis is Reported. during an Attack of Brain Stem Dysfunction Characterized by Dysarthria, Diplopia, and Ataxia, the Postcontrast CT Showed an Enhancing Lesion of the Upper Brain Stem. during a Subsequent Attack Characterized by Subcortical Dementia and Amnesia, Magnetic Resonance (MR) Showed Abnormal Signal Intensity in the Hypothalamus and Upper Brain Stem. Upon Remission of Her Symptoms, Follow-Up Contrast Enhanced CT and MR Were Entirely Normal. Magnetic Resonance is Especially Useful in Localizing Acute Inflammatory Lesions in Behçet Disease. This Case Suggests that Abnormal MR and CT Findings in Neuro-Behçet …


7li Nmr Of Normal Human Erythrocytes, Rao P. Gullapalli, Roger M. Hawk, Richard A. Komoroski Jan 1989

7li Nmr Of Normal Human Erythrocytes, Rao P. Gullapalli, Roger M. Hawk, Richard A. Komoroski

Journal of the Arkansas Academy of Science

Lithium has been known to be an effective medication for people with bipolar disorder. The mechanisms of action of lithium in the brain is not very well understood. NMR spectroscopy and imaging are effective both in determining lithium levels in tissue and brain. We have monitored lithium levels in red blood cells. We have been able to separate intra- and extracellular compartments of lithium using shift reagents, thereby obtaining T^1 's of both the compartments. Lithium uptake as a function of hematocrit was monitored weekly over a 3 week period. The time constant of 50 mM lithium uptake at 25°C …


Trace Element Nutrition. Tissue Testing Programme 1989. Residual Value. Manganese Nutrition Of Lupins., R. F. Brennan Jan 1989

Trace Element Nutrition. Tissue Testing Programme 1989. Residual Value. Manganese Nutrition Of Lupins., R. F. Brennan

Experimental Summaries - Plant Research

Evaluation of existing diagnostic procedures for the recommendation of trace element fertilizers.

To compare the accuracy and reliability of a range of tissue and soil tests being variously promoted for use to farmers for the diagnosis and prognosis of zinc and copper deficiencies in wheat crops on Western Australian farms.

Trial 66N14

Long term copper residual trial at the Newdegate Research Station.

To determine the residual value of previously applied copper.

Location: Newdegate Research Station.

Trial 86N27

Residual value of zinc with high analysis nitrogen and phosphorus fertilizer.

To determine the decline in effectiveness of zinc on this soil types …


Tactical Nitrogen Decisions For Wheat (And Nitrogen Sources Rates And Times On Wheat), J. W. Bowden, R. J. Lunt Jan 1989

Tactical Nitrogen Decisions For Wheat (And Nitrogen Sources Rates And Times On Wheat), J. W. Bowden, R. J. Lunt

Experimental Summaries - Plant Research

Trial 89MO49

Location: Tenderloin, Brand Highway, Regan's Ford.

History:

1987 Aroona wheat with 70 kg DAP and 3 kg CuSO4 at seeding followed by 60 urea at 3WAS and another 40 urea at 6WAS. Yield was about 1.7 to 1.8 t/ha;
1988 Gungurru lupins with 120 kg super and manganese/ha yielded 1.9 t/ha. 350-400 ml Roundup/ha and one cultivation prior to seeding.


Potassium Nutrition Of Pastures On The Sandplain Soils Of Western Australia., Noeleen Edwards, M. Thomas Jan 1989

Potassium Nutrition Of Pastures On The Sandplain Soils Of Western Australia., Noeleen Edwards, M. Thomas

Experimental Summaries - Plant Research

Project: Potassium nutrition of pastures on the sandplain soils of Western Australia.

Determine the factors affecting the fate of native and applied potassium on sandplain soils.
Define current and residual response curve parameters for potassium applications. Develop recommendations for the economic management of soil potassium levels.

Trial 88B46, 88TS69, 89KO26

Maintenance application rates of potassium on sandplain soils.

Location: Badgingarra Research Station, new block, North Eneabba, Kojaneerup Research Block.

Trial 89BA24

Residual value of potassium on sandplain soils.

Location: Badgingarra Research Station

Trial 89MT46,

Potassium requirements of sub clover.

Location: Mt Barker Research Station.

Project: Potassium nutrition of lupins on …


Solid-Phase Electrochemical Enzyme Immunoassay With Attomole Detection Limit By Flow Injection Analysis, Yan Xu, H. Brian Halsall, William R. Heineman Jan 1989

Solid-Phase Electrochemical Enzyme Immunoassay With Attomole Detection Limit By Flow Injection Analysis, Yan Xu, H. Brian Halsall, William R. Heineman

Chemistry Faculty Publications

A sandwich electrochemical enzyme immunoassay with flow injection analysis for the model antigen mouse IgG has been developed with alkaline phosphatase as the enzyme label. The enzyme substrate, 4-aminophenyl phosphate and its enzymatic reaction product, 4-aminophenol have been studied by cyclic and hydrodynamic voltammetry. The determination of 4-aminophenol by flow injection analysis with electrochemical detection (FIAEC) has a linear range of 5.0 × 10−8 to 1.0 × 10−5 M, a detection limit of 2.4 × 10−8 M, and a sample throughput of 72 samples/h. The detection limit is set by a background capacitance response, which depends on the ionic strength …


Preparation Of A Series Of Pyridyl Phenylureas Of Potential Agricultural Interest, Frank L. Setliff, Steve H. Rankin, Mark W. Milstead Jan 1989

Preparation Of A Series Of Pyridyl Phenylureas Of Potential Agricultural Interest, Frank L. Setliff, Steve H. Rankin, Mark W. Milstead

Journal of the Arkansas Academy of Science

Substituted phenylurea derivatives of 3-amino-2-chloro-5-methylpyridine and 5-amino-2-chloro-3- methylpyridine were prepared by treating the amines with appropriately substituted phenyl isocyanates. Structure- confirming spectral data are also presented.


Reactions Of Substituted Pyridinium Salts With Cyanide; Formation And Metal Complexes Of 2,2'Bis (Hydroxymethyl)-4,-4'Bipyridine, Dorothy N. Eseonu Jan 1989

Reactions Of Substituted Pyridinium Salts With Cyanide; Formation And Metal Complexes Of 2,2'Bis (Hydroxymethyl)-4,-4'Bipyridine, Dorothy N. Eseonu

Theses and Dissertations

The unique combination of properties of bipyridinium salts and their use in biological systems, chemical reactions, and as herbicides in agriculture have made them a discovery of major international importance. The controversy about the position of attack of the cyanide ion on the pyridine ring and the discovery of the formation of unsubstituted bipyridinium salts from the reaction of pyridinium salt with cyanide ion opened a new area of research. The current work involved a study of reactions of substituted pyridinium salts with cyanide ion. The substituted pyridinium salts were prepared by the literature methods. The 2- and 3- cyanopyridinium …


Nitrogenous Fertilisers For Cereals In Different Rotations. Results From 1989 Trials., I. Rowland, M. G. Mason Jan 1989

Nitrogenous Fertilisers For Cereals In Different Rotations. Results From 1989 Trials., I. Rowland, M. G. Mason

Experimental Summaries - Plant Research

Trial 78BA1

Nitrogen fertiliser requirement in alternate crop - pasture rotation.

Location: Badgingarra Research Station.

Trial 88B4

Effect of amount and quality of organic matter residues on response to N.

Location: Badgingarra Research Station.

Trial 86WH36, 86M44

Lupin/wheat rotation.

Location: Wongan Hills Research Station, Carrabin Research Station.

Trail 87N084, 86M39, 86ME64, 87N25, 87KA49

Pea/wheat rotation.

Location: Konnongorring, Merredin Research Station, Narembeen, Newdegate Research Station, Nyabing,


Phosphate Nutrition Of Burr Medic And Yellow Serradella., Blakely Paynter Jan 1989

Phosphate Nutrition Of Burr Medic And Yellow Serradella., Blakely Paynter

Experimental Summaries - Plant Research

Trial 89ME50, 89ME51, 89ME53, 88ME55, 89ME56

Location: Mutadgin, Doodlakine, Noongar, Mt Hampton, Nungarin

Compare the response of burr medic to topdressed P with the response of wheat to drilled P.

Trial 89ME52, 89ME54

Location: Noongar, Mt. Hampton.

Compare the response of burr medic to topdressed P with the response of wheat to drilled P.
Measure the response of burr medic pasture to applied potash.

Trial 89ME59

Location: Beacon

Compare the response of yellow serradella to topdressed P with the response of wheat to drilled P.

Trial 89ME60, 89ME61

Location: Muntadgin

Compare the response of yellow serradella to topdressed P with …


Effect Of Seed Origin And Seed Phosphorus On The Growth Of Lupins., M. M. Riley, M. D. Bolland, K. Adcock Jan 1989

Effect Of Seed Origin And Seed Phosphorus On The Growth Of Lupins., M. M. Riley, M. D. Bolland, K. Adcock

Experimental Summaries - Plant Research

Trial: 89BA29

Location: Badgingarra Research Station, Paddock 4A2, old block.

Lupin cv. Gungurru sieved to uniform size and sown without inoculation. No basal fertilizers were applied as the soil had previously been treated with high rates of superphosphate, micro-nutrients and potassium. Muriate of potash topdressed on 18/8/89 at 100 kg/ha.


Influence Of Soil Acidity On Cereals And Acidification Rates., P. J. Dolling Jan 1989

Influence Of Soil Acidity On Cereals And Acidification Rates., P. J. Dolling

Experimental Summaries - Plant Research

Soil acidity and the availability of nitrogen to cereals.

To determine the extra nitrogen available due to better pasture legume growth after liming.
To determine the extra nitrogen released from soil organic matter after liming.

Trial 89NO81

Location: South Cunderdin.

Trial 89NO82

Location: Cunderdin

Trial 89NO83

Location: Konnongorring.

Trial 89NO84

Location: Jennacubbine.

Trial 88AL35

Location: Woogenellup.

Trial 88TS54

Location: Three Springs.

Trial 88NO76

Location: Goomalling.

Trial 88NO77

Location: Ejanding.


Tactical Nitrogen Decisions For Wheat, J. W. Bowden, R. J. Lunt Jan 1989

Tactical Nitrogen Decisions For Wheat, J. W. Bowden, R. J. Lunt

Experimental Summaries - Plant Research

Trial 88MO41, 88WH40 (2CE), 88WH40 (4W), 89NO77, 89MO47, 89MO47, 89MO49, 89BA33 (1), 89BA33 (2), 89WH70 (1), 89WH70 (2)

Locations: Wannamal, WHRS, Grass Valley, Regan's Ford, Badg. New Block 3CE

In order to test tactical and other fertilizer decision making methods (Table 1), we carried out three trials in 1988 and a further seven trials in 1989 (Table 2).

To date this programme has provided a lot of information which can be used to test and validate current (and future) methods of predicting yield potential and nitrogen status of a crop as the season progresses. However, our inability to predict end …


A Strategy For The Design Of Flame Retardants: Cross-Linking Processes, Charles A. Wilkie, Sunil J. Sirdesai, Thitivat Suebsaeng Jan 1989

A Strategy For The Design Of Flame Retardants: Cross-Linking Processes, Charles A. Wilkie, Sunil J. Sirdesai, Thitivat Suebsaeng

Chemistry Faculty Research and Publications

Cross-linking is identified as an effective means for flame retardation of polymers and schemes for the cross-linking of poly(ethylene terephthalate) and poly(methyl methacrylate) are presented. For poly(ethylene terephthalate) the scheme involves polymerization of the initially produced vinyl ester. This is followed by chain-stripping, producing a polyene, and cyclization of this polyene. For poly(methyl methacrylate) the scheme entails the formation of anhydride linkages between adjacent polymer strands. Evidence is presented to show the efficacy of these processes and information is produced to aid in the identification of new flame retardants.


Nitrogenous Fertilizers For Cereals., M. G. Mason Jan 1989

Nitrogenous Fertilizers For Cereals., M. G. Mason

Experimental Summaries - Plant Research

Trial 87CI

Rates of nitrogen on continuous wheat on heavier land.
Location: North Mullewa Research Station.

Trial 80WH3, 80MI, 80N3.

Effects of Agras No. 1 on soil pH and wheat yield.
Location: Wongan Hills Research Station, Merredin Research Station, Newdegate Research Station.

Trial 78WH3

Effect of stubble treatment on nitrogen fertilizer requirement.
Location: Wongan Hills Research Station.

Trial 89WH18

Effect of banding sources of nitrogen on grain yield.
Location: Wongan Hills Research Station.

Trial 89M2 (a)

Nitrification of sources of nitrogen on heavy soil.
Location: Merredin Research Station.

Trial 89M2 (b)

Nitrification of sources of nitrogen on heavy soil.
Location: …


New Block Badgingarra Rs Late Time Of Seeding., J. W. Bowden, R. J. Lunt Jan 1989

New Block Badgingarra Rs Late Time Of Seeding., J. W. Bowden, R. J. Lunt

Experimental Summaries - Plant Research

Trial 89BA33,

Location: Badgingarra

Based on a 1.5 t/ha potential yield, the strategic treatment was planned to be 120 kg urea/ha 4WAS. However, the crop was poorly established and so NH4NO3 was used in the hope of getting better tillering than would be possible with the slower release urea source. Gambling on equal dollars to urea for 2/3 N, but believe that twice as effective.

DAP was used to place nitrogen with the seed in case there was no rain of significance after seeding. This nitrogen (only 5 kg/ha) was probably lost with the rains of 20-28/7/89 (50 mm). Urea …


Effects Of Seed Phosphorus Concentrations And The Source Of The Seed On Growth Of Lupins., M. M. Riley, M. D. Bolland, K. Adcock Jan 1989

Effects Of Seed Phosphorus Concentrations And The Source Of The Seed On Growth Of Lupins., M. M. Riley, M. D. Bolland, K. Adcock

Experimental Summaries - Plant Research

Trial 89EC31

Location: East Chapman Research Station.

The effect of seed phosphorus concentration, source of seed and fertilizer P level on plant counts from six to 20 weeks.


Plasma Polymerization By Magnetron Glow Discharge. I. Effect Of Magnetic Field On Breakdown Of Monomers In Low Pressure, K. Sato, Y. Iriyama, D. L. Cho, H. Yasuda Jan 1989

Plasma Polymerization By Magnetron Glow Discharge. I. Effect Of Magnetic Field On Breakdown Of Monomers In Low Pressure, K. Sato, Y. Iriyama, D. L. Cho, H. Yasuda

Chemistry Faculty Research & Creative Works

The breakdown voltage Vb of glow discharge of an organic monomer generally decreases as the system pressure decreases; however, below a certain threshold pressure, the breakdown voltage increases with decreasing system pressure. In the pressure range below 100 mTorr, the breakdown voltage generally increases as a linear function of 1 /p, where p is the system pressure of the reactor. In this region, glow discharge without magnetic enhancement often yields unstable discharge, which is associated with a very steep slope of a line in the Vh vs /p plot. The similar plots for glow discharges of non-polymer-forming gases, such as …


An Analysis Of The Inhibitory Effects Of Linolenic Acid Upon Photosystem Ii Of Higher Plants, Mark Edward Iven Jan 1989

An Analysis Of The Inhibitory Effects Of Linolenic Acid Upon Photosystem Ii Of Higher Plants, Mark Edward Iven

Dissertations and Theses

This study utilizes steady state fluorescence measurements, flash-induced P680+ absorption transients, and DCIP reduction kinetics to study the inhibitory effects of linolenic acid (LA) upon Photosystem II (PSII) in whole spinach chloroplasts and insideout wheat thylakoids. It confirms the presence within PSII of LA-induced inhibition of energy trapping and/or primary charge separation (i.e., primary inhibition), in addition to donor side inhibition. The latter is diminished in the presence of 1,5-Diphenylcarbohydrazide (DPC) and probably takes place at the oxygen evolving complex. Primary inhibition, which is more controversial, probably occurs between Ph and QA, with a likely contribution at the level of …


Fluorinated Esters: Synthesis And Identification, Jilla Schaff Jan 1989

Fluorinated Esters: Synthesis And Identification, Jilla Schaff

Dissertations and Theses

Reactions of different alcohols with 2-hydroxy - 1- trifluoromethyl -1,2,2-trifluoroethanesulfonic acid sultone F3CCFCF2OSO2 were studied. Six new esters were prepared: C6F5OC(O)CF(CF3)SO2F, CH3CH2OC(O)CF(CF3)SO2F, CF3CH2OC(O)CF(CF3)SO2F, (CF3)2CHOC(O)CF(CF3)SO2F, CH2=CHCH2OC(O)CF(CF3)SO2F, (CH2OC(O)CF(CF3)SO2F)2. Analytical data, infrared, nmr and mass spectra are presented supporting the proposed structures for these new compounds.


Study Of Photolytic Interference On Ho Measurements By Lif-Fage, Carmen Ivette Martinez Jan 1989

Study Of Photolytic Interference On Ho Measurements By Lif-Fage, Carmen Ivette Martinez

Dissertations and Theses

For many years there has been a great interest among the scientific community in the study of the hydroxyl radical, HO. This interest stems from the fundamental role played by this molecule in the photochemistry of the atmosphere, mainly as a cleansing agent of environmental pollutants. Knowing the concentration of the radical would enable scientists to corroborate current atmospheric models and to predict future trends in the atmosphere. Even though there is a great interest in the determination of atmospheric concentrations of this molecule, the task has been very difficult. This is mainly due to the lack of a method …


Fluorinated [Beta]-Sultones As Precursors To Fluorinated Sulfonic Acids, And New Fluorosulfonyl Containing Monomers/Polymers, Javid Mohtasham Jan 1989

Fluorinated [Beta]-Sultones As Precursors To Fluorinated Sulfonic Acids, And New Fluorosulfonyl Containing Monomers/Polymers, Javid Mohtasham

Dissertations and Theses

Sulfur trioxide (SO₃) adds to fluoroolefins of the form RCF=CF₂, (where R = F, SF₅, CF₃, CF₃OCF₂, CF₂=CF(CF₂)₂, CF₃(CF₂)₃O, CF₃O(CF₂)₂OCF₂, or CH₂ClCHClCH₂), yielding the fluorinated [beta]-sultones, RCFCF₂OSO₂. In the case of CF₃(CF₂)₃OCF=CF₂, a reverse addition occurs, giving the sultone, CF₃(CF₂)₃CF₂2OCFCF₂SO₂O. The fluoro [beta]-sultones are capable of undergoing different reactions, such as rearrangement, hydrolysis, esterification, and polymerization. These reactions, will result in the formation of compounds containing the fluorosulfonyl grouping (SO₂F); it is this group that yields the corresponding sulfonic acid upon base/acid treatment.

The addition of sodium bisulfite to CF₃CF= CF₂ and CF₃(CF₂)₄CF=CF₂ in the presence of (C₆H₅CO)₂O₂ and Na₂B₄O₇·10H₂O …


The Chemistry Of Sulfonyl Fluorides: Sf5 And/Or So2f Containing Compounds As Precursors To Sulfonic Acids, Robin Joyce Terjeson Jan 1989

The Chemistry Of Sulfonyl Fluorides: Sf5 And/Or So2f Containing Compounds As Precursors To Sulfonic Acids, Robin Joyce Terjeson

Dissertations and Theses

Sulfonyl fluoride systems and their derivatives, RS02F, where R represents hydrocarbon/fluorocarbon moieties continue to be of considerable interest. The incorporation of the sulfonyl fluoride group (S02F) into molecular systems can lead to compounds that are useful as ion-exchange resins, surface active agents, fuel cell electrolytes, and strong sulfonic acids/salts.

Interest in preparing SF5 containing sulfonyl fluorides led to the synthesis of the ᵝ-sultone, SF5CHCF20S02, and its rearranged product. Hydrolysis of the sultone gave SF5CH2S02F which led to the sulfonic acid and salt, SF …


Pasture Agronomy., C. K. Revell Jan 1989

Pasture Agronomy., C. K. Revell

Experimental Summaries - Plant Research

Trial 89ME82

a. Medic establishment.

Establishing burr medic pastures with cereal cover.
Merredin

Trial 89SC19

b. Serradella - Potash response.

Response of serradella to potash fertilizer.
South Carrabin

Trial 89M44

c. Serradella/Grass competition

Effect of grass competition on production of serradella.
Merredin Research Station.

Trial 89SC HERB

d. Herbicide tolerance of Serradella.

Herbicide tolerance of Madeira serradella.
South Carrabin


Effect Of Seed Phosphorus , Seed Size And Seeding Density On The Growth Of Wheat At Two Soil P Levels., M. M. Riley, M. D. Bolland, K. Adcock Jan 1989

Effect Of Seed Phosphorus , Seed Size And Seeding Density On The Growth Of Wheat At Two Soil P Levels., M. M. Riley, M. D. Bolland, K. Adcock

Experimental Summaries - Plant Research

Trial 89SC23

Location: South Carrabin

Effect of soil P, seed P and seed rate on plant counts at 5 weeks.
Shoot dry matter (DM) at tillering and heading and seed DM at maturity were strongly depressed by low soil P levels.


Effect Of Seed Phosphorus Levels In Three Wheat Varieties And Fertilizer P Supply On Their Growth And Grain Yields., M. M. Riley, M. D. Bolland, K. Adcock Jan 1989

Effect Of Seed Phosphorus Levels In Three Wheat Varieties And Fertilizer P Supply On Their Growth And Grain Yields., M. M. Riley, M. D. Bolland, K. Adcock

Experimental Summaries - Plant Research

Trial 89WH74

Location: Wongan Hills Research Station, Field 4W

Effect of phosphorus and fertilizer on the growth and grain of wheat yields.


Soil Acidity And Eastern Wheatbelt Plant Nutrition., W. Porter., C. L. Kipling Jan 1989

Soil Acidity And Eastern Wheatbelt Plant Nutrition., W. Porter., C. L. Kipling

Experimental Summaries - Plant Research

1. Affects of soil acidity on subterranean clover growth in the cropping areas of Western Australia.

Trial 87AL35, 87NO2, 87No3, 88NO76, 88NO77, 88TS54

To investigate the responsiveness to lime of subterranean clover based pastures on acid soil and the cropping areas of Western Australia.
To determine the reasons for responses to line in the field, particularly the possible involvement of legume nodulation effects and the alleviation of soil/water repellence.
To develop practical identification and management strategies for acid soils problems.

Trial 87AL35.

Liming in crop/pasture rotation on acid soils

Location: Woogenellup.

History: 1987 Lime applied, sown to barley
1988 Clover …


Interaction Of Season With Wheat Response To Nitrogen Fertilizer., J. W. Bowden, R. J. Lunt Jan 1989

Interaction Of Season With Wheat Response To Nitrogen Fertilizer., J. W. Bowden, R. J. Lunt

Experimental Summaries - Plant Research

Trial 89M3

Interaction of season with wheat response to nitrogen fertilizer.

Location: Merredin Research Station.

History: 1988 pasture.

Sown on 30/5/89. Gutha Wheat at 50 kg/ha Madiera Serradella at 15 kg/ha. Basal superphosphate at 200 kg/ha plus Molybdenum drilled with the seed and 100 kg/ha Muriate of Potash topdressed. At seeding (A.S) nitrogen treatments topdressed by hand on 1/6/89 and 4 weeks after (4WAS) treatments applied on 29/6/89. Supplementary water applied.

Trial 89NA61

Pasture deterioration trial.

Location: West Dale

History: Long term pasture dominated by non-productive 'suffocating clover'.

Trial 88NA88

Effect of clover growth on nitrogen for following cereals.

Location: …


Analysis Of The Potential Energy Surface Of Ar–Nh3, G. Chalasinski, S. M. Cybulski, M. M. Szczesniak, Steve Scheiner Jan 1989

Analysis Of The Potential Energy Surface Of Ar–Nh3, G. Chalasinski, S. M. Cybulski, M. M. Szczesniak, Steve Scheiner

Steve Scheiner

The combination of supermolecular Møller–Plesset treatment with the perturbation theory of intermolecular forces is applied in the analysis of the potential energy surface of Ar–NH3. Anisotropy of the self‐consistent field (SCF) potential is determined by the first‐order exchange repulsion. Second‐order dispersion energy, the dominating attractive contribution, is anisotropic in the reciprocal sense to the first‐order exchange, i.e., minima in one nearly coincide with maxima in the other. The estimated second‐order correlation correction to the exchange effect is nearly as large as a half ΔESCF in the minimum and has a ‘‘smoothing’’ effect on the anisotropy of …


Nonadditive Effects In Hf And Hcl Trimers, G. Chalasinski, S. M. Cybulski, M. M. Szczesniak, Steve Scheiner Jan 1989

Nonadditive Effects In Hf And Hcl Trimers, G. Chalasinski, S. M. Cybulski, M. M. Szczesniak, Steve Scheiner

Steve Scheiner

Nonadditive effects are calculated for (HF)3 and (HCl)3 complexes and analyzed via the combination of perturbation theory of intermolecular forces with Møller–Plesset perturbation theory (MPPT). In both systems the nonadditivity is dominated by the self‐consistent field (SCF) deformation effect, i.e., mutual polarization of the monomer wavefunctions. Heitler–London exchange and correlation effects are of secondary importance. Three‐body terms exhibit much lesser basis set dependence than the two‐body effects and even quite moderate basis sets which are not accurate enough for treatment of two‐body forces can yield three‐body effects of quantitative quality. This is due in large measure to the …