Disclaimer:  QMTools employs dialogs for a number of operations (e.g., animation, parameter editing, customization, to name just a few). In a browser environment, these dialogs can exhibit unexpected – even undesirable – modality and focus-related issues. The problems do not arise from a QMTools 'bug', but are a consequence of how different browser vendors choose to implement dialogs in applets. To wit, neither the Applet Editor nor the newer QMTools Webstart applications are plagued by such issues.

All QMTools applets share the same basic look and feel, (as seen in the Applet Editor, but without the menu bar or shortcut bar). A series of tabs is the gateway to the most important applet features.

Applet Layout

The Math tab holds the Math Palette, used for recording user input and evaluating expressions. The system potential energy and particle mass must be specified here before any quantum properties can be evaluated. Typically, the symbol "V" is used to specify the potential energy function, and the variable name mass is given to particle mass, but these assignments are discretionary: ultimately, the interpretation of these entities is derived solely from the context in which they appear, so the user is free to make potential energy and mass assignments as appropriate. Normally, potential energy and mass are first declared in the Applet Editor, though both may be changed within a running applet.

Graph tabs are labeled by the number of variables for the functions plotted, and the names of those variables. For example, from the Math tab you can plot the potential energy function, say V(x), by right-clicking anywhere in its definition field and selecting Plot Function from the popup menu. The applet automatically switches to the tab labeled Graphics: [x] where the function V(x) becomes one plot on the graph. Additional functions of the single variable x can be added to the graph by following the same procedure, but functions with a different independent variable name are assumed to belong to a different 'space' and would be graphed on a separate tab.

An Information Bar for displaying useful tidbits extends along the lower border of the applet.

The Applet Reset command button at the bottom left just above the information bar enables restoration of the applet to its condition when first loaded.

Above the information bar on the right is the Units Selector, a drop-down list box used to specify the units that accompany all numerical applet input and output.

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Choosing Applet Units

There are five preset choices covering the scales commonly encountered in quantum applications (the listed order is: energy · length · mass · time); a sixth selection handles all remaining cases.

1. eV · Å · keV/c² · fs
2. eV · nm · keV/c² · fs
3. eV · µm · eV/c² · fs
4. µeV · µm · meV/c² · ps
5. MeV · fm · MeV/c² · as
6. Flex

The femto-, pico-, and atto- time prefixes used above refer to 10⁻¹⁵, 10⁻¹², and 10⁻¹⁸, respectively.

Flex Units are those for which the measure of energy is ћ²÷2ma², where m is the particle mass and a is any convenient unit of length declared by the user. The Flex time unit is ћ divided by the unit of energy, or 2ma²÷ћ; this choice implies that the numerical value for ћ in Flex units is just unity. With Flex units, the particle mass is fully absorbed into the units, so no mass value need be specified and any such entry on the math palette is ignored.

Flex units are a convenient and common choice in atomic applications, where m is identified with the mass of an electron. If we adopt the Bohr radius (0.529 Å) as our length unit, then the Flex energy unit becomes the Rydberg (13.6 eV) and the Flex time unit is equivalent to 0.0484 fs.

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