Repeat Prob. 16.34 using MP2/6-31+G(d,p) geometry optimization followed by a single-point NMR MP2/6-31+G(d,p) calculation.
In problem 16.34
(a) For gas-phase CH3CHO, optimize the geometry at the B3LYP/6-31G* level and then use the GIAO method with B3LYP/6-31G* to find the predicted proton and 13C isotropic shielding constants (in ppm). (In Gaussian, the keyword NMR or NMR=GIAO on the line that begins with a # sign produces a GIAO calculation.) If you are using the WebMO Demo Server, you will need to click on Raw output to see the shielding constants.
(b) The TMS GIAO shielding constants for B3LYP/6-31G* are 189.78 ppm for 13C and 32.18 for the protons. Use the results of part (a) to find the predicted proton and 13C chemical shifts relative to TMS.
(c) Look up at cheshirenmr.info the recommended linear scaling constants for the method of part (a) to get scaled chemical shift predictions. Compare these with the experimental results at riodb01 .ibase.aist.go.jp/sdbs. Ignore the effect of the solvent.