Teaching Quantum Concepts in General Chemistry with Interactive Computer Software

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Teaching Quantum Concepts in General Chemistry
with Interactive Computer Software
Alan D. Crosby1 (acrosby_at_bu.edu)
Peter Carr2 Luciana S. Garbayo2 Alexander Golger1
1Department of Chemistry, Boston
University 2School of Education, Boston
University http//quantumconcepts.bu.edu
Dan Dill1 Peter S. Garik2 Morton Z. Hoffman1
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Whats the problem with teaching Quantum Concepts
in general chemistry?

• Anti-intuitive with respect to the macroscopic
  world
• Demands the suspension of belief
• Historical presentation in text books
• Supporting graphics paint misleading and
  inaccurate images
• Perpetuation of misconceptions

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Whats the problem with teaching general
chemistry?

• Passive learning with the lecture format
• Solitary learning is the norm
• Large discussion sections become mini-lectures
• TAs are often from different cultural,
  educational, and linguistic backgrounds
• Textbooks are voluminous, and increasing in
  content

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Do we really need to teach Quantum Concepts in
general chemistry?

• The future belongs to the quantum
• Nano-technology
• Quantum lasers
• Quantum computers
• The foundation of modern science
• Molecular medicine and drug design
• Biochemical interactions
• Beyond general chemistry
• Organic
• Inorganic
• Physical
• Biochemistry

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What to do?

• Develop materials to enhance learning
• Change the pedagogy to promote active learning

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Project design basic principles

• Quantum concepts unify the teaching of general,
  organic, inorganic, and physical chemistry.
• Quantum concepts force us to confront how we know
  what we know about the physical world.
• Students learn best through direct exploration
  and discovery.

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Project summary

• Visually oriented tools based on real-time
  rigorous numerical calculations.
• Fun to use while discovering and exploring key
  features of fundamental quantum concepts.
• Enable students to grasp the essence of the
  quantum concepts.
• Builds a foundation upon which the teaching of
  modern chemistry is based.

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Current project modules

• Schrödinger Shooter
• Energy levels and wavefunctions that are
  solutions to the Schrödinger Equation in a given
  potential.
• Atomic Explorer
• Energy levels and shapes of atomic orbitals.
• Bond Explorer
• Bonding and energy levels for overlapping atomic
  orbitals to create molecular orbitals.
• Diatomic Explorer
• Bonding and energy levels for diatomic molecules.

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Project modules in development

• Hybridization Explorer
• Potential energy surfaces and the force field
  that results in the directional bonding of key
  elements (e.g., B, Be, C, N, and O).
• Reactivity Explorer
• An extension of the concepts developed in the
  Bond and Hybridization Explorers examine the
  force field that determines the reaction sites.
• Spectral Explorer
• Display laboratory spectra and compare with
  spectra that can result from energy transitions
  between molecular or atomic energy levels.

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Curriculum reform

• Use of peer-led workshop model in honors level
  general chemistry
• Required reading of text and supplementary
  material
• Detailed discussions, group activities, and
  demonstrations in lecture section
• Workshops on quantum concepts
• Development of semi-quantitative understanding
• Use of interactive software for active learning

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Group investigations

• Discussion of wavefunction value, curvature, and
  kinetic energy (the Schrödinger Equation) without
  mathematics
• curvature of ? ? - kinetic energy ?
• Sketching of wavefunctions for different simple
  potential energy functions
• Free electron
• Linear ramp potential
• Infinite vertical wall (particle in a box)
• Finite vertical wall (particle escapes)
• Variation of total energy
• Normalization

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Where are we?

• Current application of PLTL
• Honor-level general chemistry
• Physical chemistry/quantum concepts
• Inorganic chemistry
• Development of advanced materials for physical
  chemistry based on the modules

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Where are we going?

• PLTL across the curriculum
• Introduction of the modules in other courses

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Shooter workshop overview

• Part I develop understanding
• Qualitative feel for the Schrödinger Equation
  qualitative and semi-quantitative interpretation.
• Physical interpretation of potential energy
  functions, wavefunctions, and probability.
• Free-hand sketching of expected wavefunctions for
  simple potential energy functions.
• Part II use the Schrödinger Shooter
• Verify the results from Part I.
• Examine more realistic potential energy
  functions.
• Collect energy values as functions of quantized
  parameters.
• Discover the origin of quantum numbers.

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Acknowledgements

• Project funding
• Current US Department of Education, Fund for the
  Improvement of Post Secondary Education (FIPSE),
  Award P116B020856, "Exploring Quantum Concepts in
  Chemistry Active Discovery by Students in the
  General Chemistry Course."
• Previous NSF Grant REC 9554198 and a NSF
  minigrant subcontract from the University of
  Northern Colorado (REC-0095023).

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How the Schrödinger shooter works

• Real-time Cooley-Numerov integration
• Many potential energy functions
• Adjustable interface of parameters
• Multiple views and visualizations
• Value of the wavefunction (amplitude)
• Amplitude squared (probability)
• Range of parameters
• Potential, kinetic, and total energy depiction