Skoog Solution of Chapter 15
Skoog/Holler/Crouch Principles of Instrumental Analysis, 6th ed.
Chapter 15 Instructor’s Manual
CHAPTER 15
15-1. In a fluorescence emission spectrum, the excitation wavelength is held constant and the emission intensity is measured as a function of the emission wavelength. In an excitation spectrum, the emission is measured at one wavelength while the excitation wavelengths are scanned. The excitation spectrum closely resembles an absorption spectrum since the emission intensity is usually proportional to the absorbance of the molecule. 15-2. (a) Fluorescence is the process in which a molecule, excited by the absorption of
radiation, emits a photon while undergoing a transition from an excited singlet electronic state to a lower state of the same spin multiplicity (e.g., a singlet → singlet transition). (b) Phosphorescence is the process in which a molecule, excited by the absorption of
radiation, emits a photon while undergoing a transition from an excited triplet state to a lower state of a different spin multiplicity (e.g., a triplet → singlet transition). (c) Resonance fluorescence is observed when an excited species emits radiation of
the same frequency at used to cause the excitation. (d) A singlet state is one in which the spins of the electrons of an atom or molecule
are all paired so there is no net spin angular momentum (e) A triplet state is one in which the spins of the electrons of an atom or molecule
are unpaired so that their spin angular moments add to give a net non-zero moment. (f) Vibrational relaxation is the process by which a molecule loses its excess
vibrational energy without emitting radiation.
1
Principles of Instrumental Analysis, 6th ed. (g)
Chapter 15
Internal conversion is the intermolecular process in which a molecule crosses to a
lower electronic state with emitting radiation. (h) External conversion is a radiationless process in which a molecule loses
electronic energy while transferring
Chapter 15 Instructor’s Manual
CHAPTER 15
15-1. In a fluorescence emission spectrum, the excitation wavelength is held constant and the emission intensity is measured as a function of the emission wavelength. In an excitation spectrum, the emission is measured at one wavelength while the excitation wavelengths are scanned. The excitation spectrum closely resembles an absorption spectrum since the emission intensity is usually proportional to the absorbance of the molecule. 15-2. (a) Fluorescence is the process in which a molecule, excited by the absorption of
radiation, emits a photon while undergoing a transition from an excited singlet electronic state to a lower state of the same spin multiplicity (e.g., a singlet → singlet transition). (b) Phosphorescence is the process in which a molecule, excited by the absorption of
radiation, emits a photon while undergoing a transition from an excited triplet state to a lower state of a different spin multiplicity (e.g., a triplet → singlet transition). (c) Resonance fluorescence is observed when an excited species emits radiation of
the same frequency at used to cause the excitation. (d) A singlet state is one in which the spins of the electrons of an atom or molecule
are all paired so there is no net spin angular momentum (e) A triplet state is one in which the spins of the electrons of an atom or molecule
are unpaired so that their spin angular moments add to give a net non-zero moment. (f) Vibrational relaxation is the process by which a molecule loses its excess
vibrational energy without emitting radiation.
1
Principles of Instrumental Analysis, 6th ed. (g)
Chapter 15
Internal conversion is the intermolecular process in which a molecule crosses to a
lower electronic state with emitting radiation. (h) External conversion is a radiationless process in which a molecule loses
electronic energy while transferring