Fortran Subroutines for Use in Physical Chemistry A package of interactive F4 subroutines has been prepared and found useful for a number of physical chemistry problems. Most of these subroutines involve the plotting of data on a TSP-212 X-Y plotter using a PDP-10 computer. Axes with titles including subscripts, exponents, small letters and most Greek letters can be drawn. A spline eurve, or least squares polynomial line or curve can be drawn through the points as a dotted, dashed, or solid line. Some of the subroutines can be used more generally and do not require a plotter. These include ACCTTY which accepts up t o 100 data points on the teletype. These can be corrected, stored in a disk file, differentiated, and smoothed. Previously stored data can be recalled. INTDAT and INTFNX integrate between any specified limits the areas under a spline eurve through data points or under a function of X, respectively. ROOTS can find the roots of any specified funetion within a given range. LSQPOL calculates the coefficients for the least squares line or polynomial and the standard errors in the coefficients. CALCYY interpolates on a spline eurve through a given set of points. Interesting problems using these subroutines include the following: solving van der Wad's equation for V, caleulating fugacities of a gas by integration, calculation of absolute entropies from handbook heat capacity data, calculation of heat capacity of solids from the full Debye equation with its integral, calculation of the eutectie temperature and composition far a n ideal solution, and calculating the intensity of black body radiation within certain wavelength ranges. In addition t o the subroutines, one main program, GPPLOT.F4 is available. I t is a general point plotting program and requires no knowledge of Fortran or programming, and has been used by a class of quantitative analysis students. I t uses m a w of the subroutines and runs in 13K of core. .4 l ~ s t i nand ~ : decmptwn id all suhroutinrs and GPI'I.OT will he sen1 tu anyone for $4 tu rover posrngt- and prepamlion costs. For anyone nrrually planning to use t h e cntire package it would he better to send a m a g n ~ t wtape on which wr could reeonl the entrrr i w t r a n version ul the ~uhrolltinrsandGPPLO'I'. Even though they h a w hrrn in use mure than two years and should he reasonably error-free, I shall be happy to answer any questi&s concerning these subroutines or to correct any errors found. Western Michigan University Kalamazoo, 49008
776 / Journal of ChemicalEducation
Robert H u n t Anderson
