National Computational Science Leadership Program (NCSLP) 1 Explorations in Computational Science: STELLA Chemistry Presenter: Robert R. Gotwals, Jr. (“Bob2”) Shodor Education Foundation, Inc.

National Computational Science Leadership Program (NCSLP) 2 Workshop Logistics l Computational Science in chemistry l Sample Curricula l Case Studies using STELLA »Simple kinetics »Lotka damped/undamped oscillating reactions »Model with lab-integrated data

National Computational Science Leadership Program (NCSLP) 3 Why Computing in Chemistry? The underlying physical laws necessary for the mathematical theory of a large part of physics and the whole of chemistry are thus completely known, and the difficulty is only that the exact application of these laws leads to equations much too complicated to be soluble. P.A.M. Dirac 1929

National Computational Science Leadership Program (NCSLP) 4 Sample Curricula l Structure of Matter »Atomic theory and structure »Chemical bonding »Nuclear chemistry l States of Matter »Gases, liquids, solids, solutions l Reactions »Reaction types »Stoichiometry »Equilibrium and kinetics »Thermodynamics l Descriptive Chemistry »Organic chemistry

National Computational Science Leadership Program (NCSLP) 5 Pedagogical Question Computational (chemistry education) or (Computational chemistry) education

National Computational Science Leadership Program (NCSLP) 6 ODEs to STELLA l Sample set of equations: »dA/dt = aA-bB »dB/dt = bB - cC »dC/dt = cC - eC

National Computational Science Leadership Program (NCSLP) 7 Case Study #1: Simple Kinetics l for the reaction: »A -- k1 --> B -- k2 --> C –with A [0] =3.6 moles –k 1 = 0.8/minute –k 2 =0.6/minute l determine the concentrations of A, B, and C over a period of 10 minutes l STELLA tools »Stock, flow, converter, connector »Numerical display, graphing tool, and table tool

National Computational Science Leadership Program (NCSLP) 8 Case Study #2: Lotka Damped/Undamped Oscillations l Application: oscillations in chemistry l Algorithm: Lotka differential equations l Architecture: STELLA l Parameters: »[A]=1.0 »[X] 0 =0.15 moles »[Y] 0 =0.01 moles »[Q] 0 =0.0 moles »k 1 =0.3 »k 2 =0.6 »k 3 =0.4

National Computational Science Leadership Program (NCSLP) 9 Case Study #2: Oscillating Version

National Computational Science Leadership Program (NCSLP) 10 Integrating Data l Goal: build a STELLA model that integrates and extrapolates l Application: calibrating a “calorimeter” l Data: provided on handout l Determine the “cooling factor” of the styrofoam calorimeter