(b) Write out the equations for the time dependence of ρ11, ρ22, ρ12 and ρ21 assuming that a light field interaction V = -μ12Ee iωt + c.c. couples only levels |1> and |2>, and that the excited levels exhibit spontaneous decay. (8 marks) (c) Under steady-state conditions, find the ratio of populations in states |2> and |3>. (3 marks) (d) Find the slowly varying amplitude ̃ ρ 12 of the polarization ρ12 = ̃ ρ 12e iωt . (6 marks) (e) In the limiting case that no decay is possible from intermediate level |3>, what is the ground state population ρ11(∞)? (2 marks) 2. (15 marks total) In a 2-level atom system subjected to a strong field, dressed states are created in the form |D1(n)> = sin θ |1,n> + cos θ |2,n-1> |D2(n)> = cos θ |1,n> sin θ |2,n-1>

The Quantum Theory of Light

SIMPSON: a general simulation program for solid-state NMR spectroscopy.

NMR Studies of Cyclodextrins and Cyclodextrin Complexes

https://spin.niddk.nih.gov/bax/lit/508/16.pdf

Investigation of complex networks of spin-spin coupling by two-dimensional NMR

We describe solid-state nuclear magnetic resonance (NMR) measurements on fibrils formed by the 40-residue β-amyloid peptide associated with Alzheimer's disease (Aβ1-40) that place constraints on the identity and symmetry of contacts between in-register, parallel β-sheets in the fibrils. We refer to these contacts as internal and external quaternary contacts, depending on whether they are within a single molecular layer or between molecular layers. The data include (1) two-dimensional 13C-13C NMR spectra that indicate internal quaternary contacts between side chains of L17 and F19 and side chains of I32, L34, and V36, as well as external quaternary contacts between side chains of I31 and G37; (2) two-dimensional 15N-13C NMR spectra that indicate external quaternary contacts between the side chain of M35 and the peptide backbone at G33; (3) measurements of magnetic dipole−dipole couplings between the side chain carboxylate group of D23 and the side chain amine group of K28 that indicate salt bridge interact...

/pdf/experimental-constraints-on-quaternary-structure-in-56zrnj6jni.pdf

Experimental Constraints on Quaternary Structure in Alzheimer's β-Amyloid Fibrils†

dipolar-assisted rotational resonance in magic-angle spinning NMR

Two recently proposed 13C–13C recoupling methods under magic angle spinning (MAS), resonant interference recoupling (RIR), and 13C–1H dipolar-assisted rotational resonance (DARR), are examined on a common theoretical foundation using the average Hamiltonian theory. In both methods, a rf field is applied on not 13C but 1H to recouple the 13C–1H dipolar interactions, and spectral overlap necessary to conserve energy for 13C–13C polarization transfer is achieved by the 13C–1H dipolar line broadening. While DARR employs time-independent 13C–1H interactions recoupled by suitable rf irradiation to 1H spins, RIR uses time-dependent 13C–1H interactions modulated appropriately by 1H rf irradiation. There are two distinct cases where 13C–1H line broadening realizes 13C–13C spectral overlap. For a pair of a carbonyl or aromatic carbon and an aliphatic carbon, spectral overlap can be achieved between one of the spinning sidebands of the former 13C resonance and the 13C–1H dipolar powder pattern of the latter. On the ...

/pdf/13c-1h-dipolar-driven-13c-13c-recoupling-without-13c-rf-54m3w2swzo.pdf

13C–1H dipolar-driven 13C–13C recoupling without 13C rf irradiation in nuclear magnetic resonance of rotating solids

We have studied the proton spin‐lattice relaxation times (T1) of a series of benzoic acid (BAC) derivatives and decanoic acid (DAC) over a wide range of temperature and analyzed the results in terms of the double proton switching along the hydrogen bonds. The proton T1 in the high temperature region are analyzed using the classical jump model and the barrier heights for the proton transfer are determined. The thermodynamic parameters for the equilibria between the two configurations in the solid state are also determined by the FT–IR measurements. It is shown that the energetics and dynamics of the proton transfer in DAC and the para‐ and meta‐substituted BAC are all similar, but they are very different in the ortho‐substituted ones. It is suggested that the low temperature behavior of the proton T1 of the dimers of carboxylic acid is due to the tunneling and the asymmetry of the potential brings in a small activation energy.

An NMR relaxation study on the proton transfer in the hydrogen bonded carboxylic acid dimers

A study on the proton transfer in the benzoic acid dimer by 13C high-resolution solid-state NMR and proton T1 measurements

Etude de polymere atactique isotactique et syndiotactique. Comparaison avec le spectre en solution

Takehiko Terao

Papers

dipolar-assisted rotational resonance in magic-angle spinning NMR

13C–1H dipolar-driven 13C–13C recoupling without 13C rf irradiation in nuclear magnetic resonance of rotating solids

An NMR relaxation study on the proton transfer in the hydrogen bonded carboxylic acid dimers

A study on the proton transfer in the benzoic acid dimer by 13C high-resolution solid-state NMR and proton T1 measurements

High-resolution solid-state carbon-13 NMR of poly(vinyl alcohol): enhancement of tacticity splitting by intramolecular hydrogen bonds