Teaching Quantum Concepts in General Chemistry with Interactive Computer Software

1. Teaching Quantum Concepts in General Chemistry with Interactive Computer Software Alan D. Crosby1 – (acrosby@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

2. What’s 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

3. What’s the problem with teaching general chemistry? • Passive learning with the lecture format • Solitary learning is the norm • Large discussion sections become mini-lectures • TA’s are often from different cultural, educational, and linguistic backgrounds • Textbooks are voluminous, and increasing in content

4. 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

5. What to do? • Develop materials to enhance learning • Change the pedagogy to promote active learning

6. 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.

7. 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.

8. 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.

9. 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.

10. 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

11. Group investigations • Discussion of wavefunction value, curvature, and kinetic energy (the Schrödinger Equation) without mathematics: curvature of ψ∝- kinetic energy × ψ • 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

12. 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

13. Where are we going? • PLTL across the curriculum • Introduction of the modules in other courses

14. “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.

15. 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).

16. 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