Distribution of Chemical Education Software G. L. Breneman Eastern Washington University Cheney. WA 99004
I t is generally acknowledged that the development of educational software is a very lengthy process and that wide distribution of such software is vital to prevent costly duplication of effort. There is a t present no single source for such distribution, but one of major importance has been THIS JOURNAL. Articles descrihine new software aooear almost monthly and the vast majority of authors offer the software to others. It is sometimes auestioned whether very many oeoole request the an effective software distribution mechanism? This paper reports the results of a three-year study of these questions. This study was part of an NSF-funded project entitled "Development and Dissemination of Computer-Based Undergraduate Teaching Materials for Chemistry" which began February 1977. Thirty-two programs were developed and reported in THIS JOURNAL (1-7) with an offer to furnish copies on request. Requests for these and previously devel(8-11) received over a period of one and oneoped half years (August 1978 to February 1980) were followed up w i t h ~ aquestionnaire sent one year after the requested programs were sent. The following information was solicited: Type of computer you have? Program(s) ran successfully on your computer? Estimated number of students using the programs? Programs used in what course(s)? Three hundred and fifty-five requests for 1134 programs were received with questionnaires being sent out one year later from August 1979 to February 1981. since then, 151 responses have been received plus 5 returned by the post office hecause of address problems. Table 1 lists the number of computers of different types being used. Some people listed more than one type. Of the 151 responses received, 75 indicated the programs had been used successfully. Of the 76 not using the programs, the majority indicated they were planning on using them but had to this m i n t lacked the time or eauioment or had been on leave the previous year. These resuits-indicate that many people do reouest the . nroerams r e ~ o r t e din THIS JOURNAL,and ap" proximately 21% of the programs requested are put into use within the first year with others possibly put into use later. The total number of students reported to have used one or more of the programs in the one year period was 3373. Three schools successfully running the programs did not report a number. A fourth school had made the programs available on a statewide network accessible by 33 universities and colleges hut no numbers of students were estimated. In general, the programs were used in courses for which they were designed. For each location where the programs are put to use, an average of approximately 45 students make use of them in a one-vear period.
. ~ - ~ ~ ~ ~ ~
~
.~
~~~
~
Table 1.
ComDuter Tvoes
Computer
,Number of Users
PDP-11 TRS-80 (Model 1)
10 10 7 7 6 3 or less each type
Anole I1 77
HP-2000 and 3000 PDP-10 others I34 types)
received from 39 countries and territories plus the United States. That comes to 2.1 ororrams wer dav (inchdine- holi. days, weekends, and vacations) for almost a decade. To get an overall estimate of the results for the eight year period assume that the student use per program sent is constant and that the average useful lifetime oer Droaram is 10 years (some have been Lsed this long already). These assumotions lead to (6172/1134) X 10 X 3373 = 183,582 students. This is a minimum number as more programs may be first put into use after the initial one year period covered by the survey. Also some people not responding may be using the programs. These results indicate that many people request programs described in THIS JOURNALand use them in significant numbers with numerous students affected. (Many of these programs are also being distributed by mechanisms other than THIS JOURNAL.These include a couple program exchanges (one in Europe), some state networks, and one commercial source. There are no statistics available on these other mechanisms but a conservative estimate might he that altogether these equal the distribution done through THIS JOURNAL.This would lead to over 'h million students using the programs.) This work was partially supported by NSF Grant No. SED76-02103.
MOLPLOT-Displaying Results of MO Calculations John J. Houser The University of Akron Akron, OH 44325 The popularity of the semiempirical MO methods in research applications remains high, and in many colleges, they are being used in physical and quantum chemistry courses. A recent paper in THIS JOURNAL(12) suggested that they be made the core of a ohvsical organic course. While such programs are fairly simple to useand, a t least for the moreapproximate methods, consume acceptably little time on a mainframe computer, there remaina few obstacles to their widespread use as teaching tools. First the output is normally strictly tabular. The user must determine the results of geometry optimization, for example, by plotting the calculated cartesian or internal coordinates. This rapidly becomes a chore if more than a few bond lengths or aneles are of interest. At least one nroeram. 358 " . " . QCPE (Extended Hiickel), outputs a printer plot of projections of the molecule in three oeroeudicular olanes. hut this is onlv coefficients in the HOMO ~ ~ ~ ' L u M o . To overcome these two difficulties, I havewiitten a compiled BASIC program, MOLPLOT, to run on t h e IBM-PC, equipped with a graphics monitor and a t least 48K of memory. This program has been used to good advantage several times in discovering an unreasonable geometry produced by an MO oroaram when it converged to a false minimum. MOLPLOT accepts as input the cartesian coordinates of the atoms and the HOMO anil LUMO coefficients, if desired. The molecules is then disnlaved on the screen in any of a number of ways. structure isshown initially as a projection in the X , Y ; Y,Z;or X.Z danes. It can then he rotated clockwise or counter. . clockwise through any integral or nonintegral angle ahout the three axes. Rotation continues until the space bar is pressed. The image can he moved left, right, up, orbown on the screen by means of the single letter commands 1, r, u, and d, and again the action continues until any key is pressed. The image may he enlarged or shrunk by use of the commands e and s, which are a~so'ie~etitive. ~ h e o ~ e r a t i o caused ns by these six commands accelerate as they repeat; thus the image may he moved about with great rapidity.nother unique feature of MOLVolume 60 Number 9
Se~ternber1983
731
are: initial display of structure, 0.3; redrawing after translation or size change, 0.2; stereo pair drawing, 1.5; HOMOILUMO drawing, 0.7. The program is currently dimensioned for forty atoms. MOLPLOT occupies 38K of memory, while the input file for a thirty atom system occupies 1.25K. A diskette, formatted for the IBM-PC, containing the compiled program and a sample input file is available from Project SERAPHIM. MOLPLOT will run using either DOS 1.0 or 1.1.
Cyclohexane Stereochemlstry G. A. Dauphlnee and 1. P. Forrest
Figure 1. Stereo pair generated by program MOLFIOT (IBM-PC).
Dalhousie University Halifax, N.S., Canada One of the more difficult skills for organic chemistrv students to develop is visualization of s&reochemistrifrorn two-dimensional representations. This is ~articularlvevident in the drawings of cyclohexane rings that many &dents produce in their early efforts. We have used a graphics pro&in1 f i r c.!.c.lohexanesrerewhnnistry whjch h,n.i proven I;, he highly suwessiul in devt.hpinr: both visual~zationaptitude and drawine skills The program functions in three sections, each section being individually accessible. The first section is non-interactive and uses animation to show ring inversion of the chair conformations of cyclohexane and the consequent change of suhstituents between axial and equatorial positions. The inversion Drocess can he stoDDed .. or started a t anv time bv the student for a more careful viewing of the individual conformers. The second section is desiened to develon skills in drawine cyclohexane rings and in equatorfa1 suhstituents in the correct orientation for proper perspective. It shows the
-
l o l l 0
Figure 2. HOMO and LUMO of azuleoe as displayed by MOLKOT (IBM-PC). PLOT is that the set of molecular cnordmates rorrespnnding to the most recent Image may be ~ a v e din a dlsk file w~thout overwriting the original set. A stereo pair Wig. I ) may beoh. tained at any time from the image currently on the srreen. Provision is made for rhansine thc marinr of the stereo oairs to improve stereopsis. ~ s a n - a i dto visualizing the stereochemistw of a molecule. a structure mav he disnlaved . . initiallv either "as is"or as its mirror image. This image can of course he manipulated as above. T h e final feature of MOLPLOT is that one may enter and display a s circles on the X,Y plane projection, either the HOMO or the LUMO coefficients (Fig. 2, azulene). In this image, the circles have radii proportional to the values of the coefficients, and positive coefficients are shaded in. Hydrogens are eliminated from these structures for improved clarity. All images remain on the screen until the space bar is struck, and they may he hardcopied with the IBMIEpson printer if it is equipped with a graphics ROM and if one of the currently available screen-dump modifications of DOS (14) is in use. These rupies make excellent werhead transparenriec as well a3 xeru-graph~ccopies, as the PC operating in the high-rwolut Ion mtdt, gives a MO X 200 field. 'l'he molecular coordinates are entered in a text file created using and the MO ctwffir~ents the 1'C line editor. EDLIN. and t h i file is called bv M01.PLOT a t run time.'~ometypical times, in seconds, needed to carry out several of the operations on a thirty atom structure
732
Journal of Chemical Education
hu tk ha14 mith tk MI? b11. tmhu IS shr k r a4 v ralurr.
h r Y l e t kIp uc 1, -4 Figure 3. Screen display during placement of equatorial bonds in program CYHX-1 (IBM-PC).
Rtss 111t n u
Yoa
tntritr
#
h r r R to 9DUl this pmbln: F to rl ntxt pnblen: use BC kg to exit. Figure 4. Stereo~hemistryproblem presented by program CYHX-1 (iBM-PC).
