1.1 Spectroscopy1.2 Nature of Electromagnetic Radiations1.3 Characteristics of Electromagnetic Radiations and Atoms/Molecules1.4 Born-Oppenheimer Approximation1.5 Schrödinger Wave Equation1.6 General Condition of Resonance, i.e. Absorption or Emission1.7 Molecular Spectroscopy and Spectral Regions1.8 Spectrum and Basic Elements of a Single and Double Beam Absorption Spectrometer1.8.1 Signal to Noise Ratio1.8.2 Resolving Power of a Spectrometer and Its Relation to Slit Width1.8.3 Width of the Spectral Lines and Factors Affecting It1.9 Intensity of the Spectral Bands (or Quantum Mechanical Treatment of Transition Between Two States)1.9.1 The Transition Probability1.9.2 Boltzmann Distribution Law and Population in Energy States1.9.3 Average Lifetime of the Excited State1.9.4 Concentration and Path Length of Sample1.10 Limit of Sensitivity of the Spectroscopic Method of Identification of Substances1.11 Fourier Transform (FT) and Computer Average Transient (CAT)1.12 Fitting of a Straight Line and Method of Least SquaresProblemsAppendix A-1.1