Vibrational frequencies and infrared intensities of dichloromethane molecules CH2Cl2, CHDCl2, CD2Cl2 in the gas phase have been calculated using the ab initio molecular orbital method with many combinations of basis set functions and electron correlation correction methods, and compared with experimental values. The dependence of calculated frequencies and intensities on basis set function and electron correlation correction method was made clear, and as a recommended combination of basis set function and electron correlation correction method, MP2/6-311G(3df, 3pd) was proposed and gave an average error of 0.93% for vibrational frequency calculation, and MP2/D95(3df, 3pd) was proposed to give an average error of 22.9% for infrared intensity calculation. However, there are numerous difficulties in the theoretical analysis of vibrational spectra when using computational chemistry methods.
It is possible to reuse the old BASIC program via Excel. It seems that none can use VBA (Visual Basic for Applications) of Excel skillfully, when he/she is not versed in the Visual Basic grammar. However, the old classical BASIC grammar is very available in VBA of Excel. It is possible to teach ingenuity in the BASIC programming in which the creative idea in the debug and error countermeasure is cultivated. Within a given function in IT (information technology), the creative idea cannot be cultivated in a mere computing process.
A program, called PLEC-1, has been developed with Visual Basic to simulate and analyze the electrochemical measurement of a polymer-coated electrode with dispersed functional molecules. The program has two independent buffers for oxidant and reductant per one material and can concurrently treat seven materials and three chemical reactions of either first- or second-order. The user can not only experience virtual cyclic voltammetry and potential-step chronoamperometry but also analyze cyclic voltammograms by the Gauss-Newton method using the program. In PLEC-1, simultaneous partial differential equations are solved by the combination of Crank-Nicolson and iteration methods.