(a)
Interpretation:
The meaning of fluorescence is to be stated.
Concept introduction:
When a substance absorbs radiation or light, it may emit or reflect it back.
(b)
Interpretation:
The meaning of phosphorescence is to be stated.
Concept introduction:
When a substance absorbs radiation or light, it may or may not emit it back.
(c)
Interpretation:
The meaning of resonance fluorescence is to be stated.
Concept introduction:
The atom can interact with fields of same frequency as them.
(d)
Interpretation:
The meaning of singlet state is to be stated.
Concept introduction:
There are magnetic spins on electrons in an atom. The magnetic spin can either be positive or negative.
(e)
Interpretation:
The meaning of triplet state is to be stated.
Concept introduction:
There are negative and positive magnetic spins on each electron in an atom.
(f)
Interpretation:
The meaning of vibrational relaxation is to be stated.
Concept introduction:
When a substance absorbs radiation or light, the molecules get excited. Then the energy is reflected back after some time.
(g)
Interpretation:
The meaning of internal conversion is to be stated.
Concept introduction:
The molecules get to the excited state by absorbing energy and come back to ground state by emitting this energy.
(h)
Interpretation:
The meaning of external conversion is to be stated.
Concept introduction:
The molecules get to the excited state by absorbing radiation and come back to ground state by emitting this radiation.
(i)
Interpretation:
The meaning of intersystem crossing is to be stated.
Concept introduction:
There is a possibility of changing states from singlet state to triplet state. It is only possible when spin orbit coupling is present.
(j)
Interpretation:
The meaning of predissociation is to be stated.
Concept introduction:
The bond of any molecule can be broken due to its unstable excited state.
(k)
Interpretation:
The meaning of dissociation is to be stated.
Concept introduction:
The bond of any molecule can be broken due to excessive absorption of energy.
(l)
Interpretation:
The meaning of quantum yield is to be stated.
Concept introduction:
The numbers of photons absorbed and emitted are different. These numbers are needed to find the yield of a substance.
(m)
Interpretation:
The meaning of chemiluminescence is to be stated.
Concept introduction:
The light that is absorbed by the molecules of a substance can be emitted because of different ways.
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Chapter 15 Solutions
Principles of Instrumental Analysis
- How many normal modes of vibration are there for (a)NO,. (b) N20. (c) cyclohexane. (d) hexane?arrow_forwardExplain the origin of (a) absorption, (b) phosphorescence, and (c) Raman spectra. You may draw the Jablonski diagram to enhance your explanation.arrow_forwardCalculate the wavenumbers of the two highest energy vibrational transitions for the 1271³5 CI molecule. [Note: m(¹271) = 126.9045 u, and m(35CI) = 34.9688 u; the vibrational wavenumber (V) is 384.3 cm³¹; the first order anharmonicity constant (X₂) is 0.0039.] - Hint: For this anharmonic oscillator, the question asks for an estimate of the type G(v+1) – G(v) = AG+2 for AG1/2 and AG3/2-arrow_forward
- Express a wavelength of 442 nm as (a) a frequency. (b) a wavenumber.arrow_forwardThe protein haemerythrin (Her) is responsible for binding and carrying O2 in some invertebrates. Each protein molecule has two Fe2+ ions that are in very close proximity and work together to bind one molecule of O2, form ing an Fe2O2 group. (a) The Raman spectrum of oxygenated haemerythrinobtained with laser excitation at 500 nm has a band at 844 cm-1 which has been attributed to the O-O stretching mode of bound 16O2. Why is Raman spectroscopy and not infrared spectroscopy the method of choice for the study of the binding of O2 to haemerythrin? (b) Proof that the 844 cm-1band in the Raman spectrum of oxygenated haemerythrin arises from a bound O2 species may be obtained by conducting experiments on samples of haemerythrin that have been mixed with 18O2, instead of 16O2 . Predict the fundamental vibrational wavenumber of the 18O-18O stretching mode in a sample of haemerythrin that has been treated with 18O2. (c) The fundamental vibrational wavenumbers for the O-O stretching modes of O2,…arrow_forward5. What is the basis of vibrational spectroscopy. Derive the expression for natural frequency for vibration of a spring with spring constant K and mass m.arrow_forward
- a) Calculate the moment of inertia of (i) H2 (ii) H2, (iii) CO2, (iv) CO2. (b) Calculate the corresponding rotational constants, expressing your answers as a frequency in hertz(Hz) and as a wavenumber in reciprocal centimeters (cm-1)arrow_forwardEstimate the lifetime of a state that gives rise to a line of width (i) 0.20 cm−1, (ii) 2.0 cm−1.arrow_forwardFor 1H35Cl molecule, (N1/N0) ratio at 300 K is 6.091 x 10-2. Calculate thewavenumber ( in cm-1) for J=2→J=3 transition in the microwave spectrum of the molecule.arrow_forward
- 5- In Trans-[PDFC1;]° determine I'total, I'tran., I'rot. and I'vib., Which mode(s) is (are) active in IR and Raman spectroscopy?arrow_forwardThe primary structure of a protein contains the peptide bond (-CO-NH-), which has the ability to form hydrogen bonds and influence protein molecular shape. (a) If the force constant of N-H bonds in non-hydrogen bonded regions of a protein is 680 Nm', predict the vibrational wavenumber value for non-hydrogen bonded N-H stretching in the infrared spectra of proteins. Show all working. (b) A hydrogen-bonded section of a protein produces a N-H stretching band at 3386 cm1 in the infrared spectrum. Determine the force constant for the hydrogen bonded N-H in the protein. Show all working. (c) Briefly describe how the presence of hydrogen bonding influences the N-H stretching mode of proteins.arrow_forward(i) Explain why Beer's Law breaks down when absorbance values are < 0.005. (ii) Explain the operation of a calcium source used in atomic absorbance spectroscopy. (iii) Explain why the calcium source described above will not operate for the quantification of magnesium.arrow_forward
- Physical ChemistryChemistryISBN:9781133958437Author:Ball, David W. (david Warren), BAER, TomasPublisher:Wadsworth Cengage Learning,Principles of Instrumental AnalysisChemistryISBN:9781305577213Author:Douglas A. Skoog, F. James Holler, Stanley R. CrouchPublisher:Cengage Learning