Problem Set 6

True or False: The spin-spin (transverse) relaxation time is the time required for the nuclear magnetic moments to lose phase coherence (the time needed for the magnetic moment to “fan out”)

Instrumentation of IR spectroscopy?  Please answer at your own words.

In the fluorescence quenching of rhodamine B dye, the fluorescence decay of rhodamine B in the DMF-solution with ethanol-water mixture was monitored by measuring the 605 nm emission lifetime (decay of intensity over time) after a laser pulse. The lifetime (t) of rhodamine B in absence of quenchers is Do 2.10 ns. Quenching of rhodamine fluorescence by the presence of 2% ethanol- water mixture reduced the lifetime (T) to 1.86 ns. Using the following Stern-Volmer equation, what would be the rhodamine B emission lifetime in ns by changing the ethanol-water to 13 %? (Final answer should be of three significant figures) 1.142 To T = k₁ + k₂+k₂ [Q] k₁ + k₁₂

I have to assign multiplicities to each of the three multiplets and coupling constants. Going from top to bottom I got Doublet, Doublet of doublet and sextet. Are my answers correct? If not what is the correct answer and how did you get to it? Thank you for your time!

5. The table shows intensities and lifetime data for luminescence of a ruthenium complex for a range of oxygen concentrations. Concentration Fluorescence Fluorescence intensity oxygen (uM) lifetime (us) 590 1.008 22 574 0.978 44 557 0.964 72 552 0.95 132 518 0.916 174 503 0.893 267 478 0.836 a. Why does the luminescence intensity decrease as the oxygen concentration increases? The luminescence intensity decreases as the oxygen concentration increases because the oxygen is acting as a quencher so when the oxygen is present the luminescence gets excited and then that energy is transferred and accepted by охудen. b. Plot a Stern-Volmer graph based on fluorescence intensity. Is the calibration linear? The calibration is c. Plot a Stern-Volmer graph based on fluorescence lifetime. What type of quenching is indicated by the plot?

Could you use a compact fluorescent light (CFL) bulb to perform UV-visibleabsorption spectroscopy? Why/why not?

What is monochronator in IR spectroscopy?  Please shortly answer at your own words.

For problems Use the provided data to identify functional groups the molecule contains and you are not expected to come up with an exact structure. propose some possible structures that fit the data 3a. C, H, N containing compound with MW 101. Only one kind of N containing functional group. O) A liquid compound with a molecular weight of 101. 4000 3500 3000 2500 2000 1500 1000 Wavenumber (cm-1) Tranamiasion

Calculate the frequency separation of the nuclear spin levels of a 13C nucleus in a magnetic field of 15.9 T given that the magnetogyric ratio is 6.73 × 107 T-1 s-1.Ans = ______  MHz. (Note: because the magnetogyric ratio of 13C nucleus is only about 1/4th of that of a proton, the frequency of resonance is also only about 1/4th of the proton resonance frequency in the same instrument.

SPECTRUM 1: C3H₂NO possible structing % Transmittance 100 95 90 85 80 75 70. 65 60 55 50 45 4000 3750 3500 3250 ***** ***** 3000 ATR 2750 2500 2250 2000 Wavenumbers (cm-1) © 2023, Sigma-Aldrich Co. ALL RIGHTS RESERVED ******* 1750 1500 ****** ****** 1250 ***** **** 1000 750

HNMR Spectroscopy..    Please solve and explain it

7) The correct structure that corresponds to the spectroscopic data given below is [IR 2720, 1710 1 point cm*1. 1H NMR 9.80(s, 1H), 7.50(dd, J = 8,0Hz, 2Hz, 1H), 7.40(d, J = 2.0Hz, 1H), 6.90(d, J = 8.0Hz, 1H), 3.90(s, 3H), 3.80(s, 3H)] COOH OMe Me CHO OMe OMe CHO OMe OMe COOH OMe Me

a.) What is the resonance frequency of a proton in a magnetic field of 14.6 T? Ans = _______ MHz b.) The rotational Raman spectrum of 35Cl2 (m(35Cl) = 34.9688 u) shows a series of Stokes lines separated by 0.9752 cm-1 and a similar series of anti Stokes lines. Calculate the bond length of the molecule. Ans = ______ Angstroms

Each peak in the spectrum below can be used to provide a measure of the mass of this protein, you can work out the charge associated with each peak, and measures can be averaged to find the overall mass. Use simultaneous equations to find the charge associated with each peak in the spectra below, which will allow you to calculate the average mass of each species. Include an estimate of the error associated with this measure. Dont use chatgpt

CHEM 301 Worksheet #4 Particle on a ring and Harmonic oscillator applications Part A Applications of particle on a ring 1. Referring to the lecture notes for the operator for angular momentum (Lz), calculate the average angular momentum for a particle on a ring. The wavefunction for particle on a ring is Y( p) = + im o 2n 2. Use the particle on a ring model to calculate the wavelength maximum for the indole ring of the amino acid Tryptophan, assuming a diameter of 458 p.m. a. Draw an energy diagram for this system.