molecule can be drawn in various perspectives in two-dimensions. Finally, the program tests the student to see if he/ she bas absorbed theinformation. If thestudent answers the test questions correctly, helshe is cycled to the next program; if not, helshe is returned to the tutorial. Programs two and four are tutorial programs that describe how ethane and butane are drawn using sawhorse or Newman projections and how the conformations of each differ in potential energy. Both programshake use of the Apple's highresolution graphics and animation effects to convey the ideas. Programs three and five are highly interactive, animated drill . Dromams that allow the student to work with either sawhorse or Newman projections or ethane or butane. The programs draw the chosen projection and begin t o randomly rotate one carbon atom. The programs then instruct the student to stop the rotation when the configuration shown corresponds to the one listed a t the bottom of the screen. If the student stops the rotation a t the wrong conformation, the program tells the student the name of theconformation on the screen. By scoring three correct answers in a row or by pressing the escape key, the student can elect to continue with the current drill, change the projection, or quit the program. All of these programs are written in Applesoft Basic and will run on an Apple II+, 48K, or Apple IIe. They vary in length from 2.6K to 6.5K. There are a number of binary files that are also necessary for operation. The programs operate from a main menu and the instructions are built into the programs. They are available from Project SERAPHIM. Acknowledgment The author wishes to acknowledge the partial support of the National Science Foundation, the RISE program, while these programs were being written. This paper was presented in part at the 185th ACS National Meeting, Washington, D.C., August, 1983.
MOLPIX-A Program tor Generating and Displaying Molecular Structures Milton D. Johnslon, Jr. University of South Florida Tampa, FL 33620 Over the past few years, several programs have been submitted to this department for the purpose of displaying molecular structur&. The most so~histicated. Droerams are generally intended for display with mainframes or minicomouters. MOLPIX is aset of routines snecificallv designed for use on a microcomputer. A student o; instructbr can-use the routines in this package to go all the way from just bond lengths and angles to completed molecular structures. T h e nroaram would be of use in anv situation where easv access to molecular coordinates and displays would be desLed. The program is written in advanced Basic and runs on an IBM PC with, preferably, 128K of memory and a t least one 320K (DS-DD) f l o u ~ ydisk drive. Anv standard color or color graphics terminali"ffices to show the completed structures. Also, any graphics-compatible dot matrix printer (e.g., an Epson FX-80) can be used to print out molecular struct,,rW2 ""A-".
Users interact with the program through a menu and various submenus. The following are the most useful features of the program: 1)
Generation 19 md~cularstructures from just lwnd lengths and hrnd angles. 'The resulting srrucrurcs can either be pnnwd out tas their (hteslan coordiuatrs) or plotted on the CHT.
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Abilitv to read in molecular structures obtained from other sources ( e g . lnolerulnr mechanics or X-ray strurturesj. A capatdity to cornhine various n,olerul~*ur f m y m m t a intrt larger integrated structures. A capability to rotate and translate nlolecnles and molecular coordinates and to rotate functional groups about a bond. Access to a table of standard bond lengths and bond angles for easv reference when seneratine molecular coordinates. Varimr editing modes which allow thr addition o r dderion of atomsor bond* and the iuappinl: of nrom indices. helectlon of \,ariousplottlny mudrs (line structures, I d - n n d stick models, etc.). A subroutine allowing the calculation of structure parameters (bond lengths and angles) for already computed structures. ~~
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Documentation is ~ r o v i d e don the ~roarammingdisk (a standard IBM-compatible, double-shed, double-density 320K disk). The menus are in a one- or two-letter mnemonic form and are designed to be easy to use. The program can he used as is or broken up into portions as needed (e.g., for compilation). The Basic coding is there for the user to alter as he or she wishes. A disk containing the program and relevant documentation and three sample data sets is available from the author for $35. Users merely desiring a listing (e.g., users with another type of computer who would like t o adapt the programs) may obtain a listing for $15 instead. Make checks payable to Milton D. Johnston, Jr.
ChemicalArithmetic on a Pocket Computer
-University of Petroleum
Patrick L. Pollet' 8 Minerals
Dhahran International Asport P.O. Box 144. LPM Box 298 Saudi Arabia The recently released "pocket computers" having a reasonable amount of nonvolatile memory, tiny printers, and a cassette interface are ideal for programming error-prone or tedious routine calculations (14). The program GIESEL accepts as input any line-type structural formula (up to 80 characters) and outputs the empirical formula and the molecular weight. Additional features include elemental percent analyses and mole-to-mass conversion. The line formula is simply entered as a linear string of symbols (upper and lower case) and coefficients following the usual chemical symbolism (KMn04 for potassium permanganate or CH3COCH(COOC2H5)2 for diethyl acetyl malonate). The "parsing" routine allows one level of parentheses and any nonchemical symbol may he added for easy reading (such as =,*, . . .). Syntax errors are flagged as well as unknown or mispelled elements. Results are normally presented on the one-line display. As an ontion. both inout and outnut mav be ~ r i n t e dA . built-in table con&ins theatomic weights of the i r s t 105 elements. This program, written in relocatable machine code (1.5K), will run on any version of the SharpPC-1500 (or T R S PC-2) and can be loaded at any convenient place before use. Within this program, provisions are made for additional user-defined commands. The resulting molecular weight and empirical formula are deposited in an area of memory accessible to the Basic interpreter for further use within an external Dropram or in calculator mode. Examples of runs are given with various compounds, both organic and inorganic, as well as massspectrometry fragments. This program and its documentation are available from the author by sending a standard audio cassette and five U.S. dollars (by check) for handling and postage.
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On leave from National Institute for Applied Sciences. Laboratory of Organic Chemistry. 20 Rue A. Einstein, 69100. Villeurbanne. France. Volume 62 Number 5
May 1985
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