Question

In this experiment you will measure the stretching frequencies of different functional groups in a series of organic molecules. Then you will compute the spectra in Gaussian. The computed spectra will be calculated in the gas phase. How is that going to affect the calculations

Answer 1

The C-C and C-H stretching frequencies in IR spectra can be used to distinguish between constitutional isomers of organic molecules.

Step-by-step explanation:

In this experiment, measuring the stretching frequencies of different functional groups in a series of organic molecules can help distinguish between constitutional isomers. The C-C and C-H stretching frequencies in IR spectra provide useful information about the presence and location of double and triple bonds in organic molecules. Each functional group has its own characteristic stretching frequency, which can be identified in the IR spectrum. By comparing the IR spectra of the four constitutional isomers, 1,2-dimethylcyclohexene, 1,3-octadiene, 3-octyne, and 1-octyne, the specific stretching frequencies of the C-C and C-H bonds can be correlated to the different isomers.

Answer 2

If infrared radiation of a given frequency strikes a sample composed of molecules having a vibrational frequency the same as that of the incident radiation, the molecules absorb radiation and the energy of the molecule is increased. However, if the incident frequency differs from the characteristic frequencies of the molecule, the radiation passes through undiminished, or in some experiments, it is reflected. The vibrational frequencies for a particular molecule are determined primarily by the masses of the atoms in the molecule and the strengths of the bonds connecting them. For a diatomic molecule, this frequency can be derived from Hooke's law and is written as:

F=1/2pi*(w/k)^1/2