Physical Chemistry Applets, Solar Photovoltaic Applet and Chinese HSK Vocabulary and Character Applets

RKT has retired from teaching but is keeping the teaching part of the website going for a while. The tutorial topics listed on the left are the Physical Chemistry topics needed to complete Part 1 (first three years) of the Oxford chemistry course. Each topic consists of recommendations of what to cover, suggestions for books to read, and a selection of problems with answers and hints. In two or three cases there are multiple choice quizzes which allow you to sharpen up your proficiency in certain areas, e.g. atomic term symbols. A particular feature is the use of applets to illustrate several more difficult aspects of physical chemistry. Applets are interactive programs that allow you to adjust parameters and observe the effects, e.g. the effect of changing the temperature on an infrared spectrum or of changing the spin-spin interaction in an AB nmr spectrum. In each case, suggestions are made for particularly useful combinations of the adjustable parameters. These have been developed particularly to teach points of principle in physical chemistry and it is hoped they will have value outside the Oxford physical chemistry course. These physical chemistry applets, together with some physics applets on the research part of the website, are listed below with direct links to them. More applets will appear on the site and suggestions for new ones or for improvements to current ones will be welcomed.

Spectroscopy Applets

Infrared Vibration Rotation Spectrum shows the vibration-rotation spectrum of a linear molecule in which the upper and lower inertial constants (B), temperature and nuclear spin statistics can be varied.

Raman Rotation Spectrum shows the Stokes and anti-Stokes lines in the rotational Raman spectrum of a linear molecule in which the inertial constant (B), distortion constant (D), temperature and nuclear spin statistics can be varied.

Nmr AB/AX Spectrum shows the effects of chemical shift difference and spin-spin splitting on the nmr spectrum of two spin 1/2 nuclei. The spectrometer field, spin-spin splitting and chemical shift differences can be varied.

Nmr and Chemical Exchange shows the effects of temperature on the nmr spectrum associated with exchange of two spins whose kinetics follows an Arrhenius behaviour. The spectrometer field, temperature and line separation can be varied.

Atomic Spectrum of Sodium shows the atomic spectrum of sodium. This has no adjustable features but the applet allows a much higher resolution picture to be displayed than normally accessible.

Fitting Atomic Spectral Lines. This applet has two purposes. The first is to demonstrate how to assign and fit simultaneously the lines in a given series. The second is as a rapid means of fitting any set of atomic spectral lines. A set of wavenumbers can be input and the least squares fitting makes it possible to extract easily and quickly the assignment, series limit and quantum defect.

Normal Vibrational Modes of a Linear XY2 Molecules. The vibrations of a triatomic molecule are shown. The masses of the molecule can be varied and the vibrations can be individually switched on and off. The phase of the two components of the bending vibration can be adjusted.

The Intensities of the Vibrational Substructure in an Electronic Band using the Franck-Condon Principle. The bond length and force constant in the upper state can be varied, the wave functions are displayed and the spectrum calculated.

Statistical Mechanics Applets

Heat Capacity of a Two Level System shows the effects of temperature, energy level separation and relative degeneracy on the heat capacity of a two level system. These three parameters can all be varied.

Simpler Version of Heat Capacity of a Two Level System is a simplified version of the above for first year students.

Rotational Heat Capacity of a Diatomic Gas shows the effects of rotational constant, temperature and spin statistics on the rotational heat capacity of a diatomic gas. It also shows the variation of the population of the energy levels.

Heat Capacity of Solids compares the Einstein and Debye models of the heat capacity. The adjustables are the Einstein frequency and Debye cut-off. The plot can be switched from a linear function of temperature to the quadratic variation for the extrapolation of the heat capacity at low temperature.

Vibrational Heat Capacity of a Diatomic Gas shows the variation of the heat capacity of a diatomic gas and the energy levels as a function of vibrational energy level spacing and temperature.

Kinetics Applets

Kinetics in the Steady State compares the exact, the steady state and the equilibrium solutions for the kinetics of a two step reaction, allowing you to explore the range of validity of the steady state approximation. The three rate constants can be varied.

Michaelis-Menten Kinetics of Enzyme Reactions compares the exact and steady state solutions for a simple enzyme reaction. The rate constants and the ratio of enzyme to substrate can be varied.

Liquids and Solutions Applets

Molecular Dynamics Simulation shows a molecular dynamics simulation and the radial distribution function for a two dimensional assemly of atoms. The temperature and density of the particles can be varied.

Virial Coefficient of a Gas calculates the virial coefficient of a gas as a function of temperature for a simple square wave potential. The parameters of the potential can be varied.

Vapour Pressure in a Mixture calculates the vapour pressure of two components of a mixture as a function of the enthalpy of interaction. The parameters of the potential can be varied.

Ising Model of Mixing is a simulation of mixing according to the Ising model. A number of interesting things can be demonstrated with this simple model. The simulation can be done at different values of the interaction parameter, at different temperatures, and at different starting points for the demixed phases.

Phase Separation of Two Liquids calculates the phase diagram for mixing of two liquids, ranging from ideal mixing to strong demixing. The enthalpy of interaction and the temperature can be varied.

Gibbs Adsorption Isotherm relates the change in surface tension with concentration to the amount adsorbed at the surface. This is a difficult relation to understand and the applet makes it possible to vary the maximum coverage.

Polymer Applets

Configuration of a Polymer (3D Random Walk) shows the wide range of configurations adopted by a polymer obeying the random flight model. These can be repeated and averages derived in the simulation.

Applets for Optical Reflection from Films and Diffraction from Slits and Arrays

Reflection of Light from a Thin Film shows the effect of a thin film on the reflection of light from a flat surface. The wavelength of the light, the thickness of the film and the refractive indices can be varied.

Newton's Rings shows Newton's rings from a thin polymer film on silicon. The thickness of the film and the variation of the thickness can be altered. The wavelength of monochromatic light may be varied or the pattern may be displayed in white light.

Interference of Light at Slits (Young's Slits) shows the diffraction pattern from a set of up to six slits. The wavelength of light, the size, spacing and number of the slits, and the wavelength of the light can be varied.

Interference of Light from an Array of Apertures shows the diffraction pattern from an array of apertures whose size, shape and separation can all be altered. This is an applet designed to help the understanding of surface diffraction, e.g. LEED.

Solar Photovoltaic Applet

Solar photovoltaic power can be set up under very favourable terms on the UK Government's Feed-in-Tariff (FIT) scheme. The applet does a full interactive calculation of how solar power can be expected to vary with time of day, month and year, with orientation and tilt of roof, and approximately with latitude. Average daily, monthly and annual output can be calculated for any of these conditions. There is also discussion of how the funding scheme works.

Applets for Learning Chinese

HSK Level 1 , HSK Level 2 and HSK Level 3 Chinese vocabulary testsare programs for teaching yourself Chinese vocabulary using the nationally approved HSK classification of words. The.Chinese character test is a program for teaching yourself Chinese characters. The range of characters can be chosen so that it is suitable for beginners and those who are quite advanced. For those who are new to Chinese, there is much more to learning the language than just the characters. However, they are a major component and they are extraordinarily interesting to learn.