PerfectBASH-Entkopplung:
2 The strongly coupled case: Analysis using density matrices
2.1 Details of the calculation
S9
S10
with their eigenvalues of HAB denoted as a, b, c and d, whereas 4 :
2
2 2
2 2
(2.2) The density operator ρ(t) after passing through the pulse sequence in Figure 2-1 is given by
(2.3)
using exponential propagators for pulses and times of free evolution. Since the AB system under consideration is strongly coupled, the corresponding Hamiltonian HAB for free evolution is used:
2 ∙ 2
(2.4) The initial state ρ0 after the 90°x pulse is given by
〈 〉 〈 〉.
(2.5)
The expectation value for transversal magnetization during the free induction decay is obtained by taking the trace of the matrix representation of ρ(t) multiplied with the matrix representation for the transversal magnetization F+:
〈 〉
(2.6)
2.2 Results of the density matrix calculations
The result is of the general form hF+i = X
j
Aj·exp [i(ωj,1τ1+ωj,2τ2+ωj,3τ3+ωj,4(τ4+t2))] (2.7)
and consists of the 72 terms, listed in Table 2.1:
Table 2.1: Results from the density matrix calculations
Amplitude factor Exponential factor Term No.
−i2pq(q+p)4 p2−q22
ei((b−d) (τ4+t2)+(c−d)τ3+(b−d)τ2+2(d−b)τ1) 1 ip2q2(q+p)2 p2−q22
ei((c−d) (τ4+τ3+t2)+(b−d)τ2+2(d−b)τ1) 2
−2ip3q3(q+p)4 ei((b−d) (τ4+τ3+τ2+t2)+2(d−b)τ1) 3
−ip2q2(q+p)2 p2−q22
ei((c−d) (τ4+t2)+(b−d) (τ3+τ2)+2(d−b)τ1) 4
−2i(q+p)2 p2−q24
ei((b−d) (τ4+t2)+(c−d)τ3+(b−d)τ2+(2d−c−b)τ1) 5 ipq p2−q24
ei((c−d) (τ4+τ3+t2)+(b−d)τ2+(2d−c−b)τ1) 6
−2ip2q2(q+p)2 p2−q22
ei((b−d) (τ4+τ3+τ2+t2)+(2d−c−b)τ1) 7
−ipq p2−q24
ei((c−d) (τ4+t2)+(b−d) (τ3+τ2)+(2d−c−b)τ1) 8
i
2pq p2−q24
ei((b−d) (τ4+t2)+(c−d)τ3+(b−d)τ2+2(d−c)τ1) 9
−ip2q2(p−q)2 p2−q22
ei((c−d) (τ4+τ3+t2)+(b−d)τ2+2(d−c)τ1) 10 2ip3q3 p2−q22
ei((b−d) (τ4+τ3+τ2+t2)+2(d−c)τ1) 11 ip2(p−q)2q2 p2−q22
ei((c−d) (τ4+t2)+(b−d) (τ3+τ2)+2(d−c)τ1) 12
−2ipq p2−q24
ei((c−d) (τ4+t2)+(b−d)τ3+(c−d)τ2+2(d−b)τ1) 13
−ip2q2(q+p)2 p2−q22
ei((b−d) (τ4+τ3+t2)+(c−d)τ2+2(d−b)τ1) 14 ip2q2(q+p)2 p2−q22
ei((b−d) (τ4+t2)+(c−d) (τ3+τ2)+2(d−b)τ1) 15
−2ip3q3 p2−q22
ei((c−d) (τ4+τ3+τ2+t2)+2(d−b)τ1) 16
−2i(p−q)2 p2−q24
ei((c−d) (τ4+t2)+(b−d)τ3+(c−d)τ2+(2d−c−b)τ1) 17
−ipq p2−q24
ei((b−d) (τ4+τ3+t2)+(c−d)τ2+(2d−c−b)τ1) 18 ipq p2−q24
ei((b−d) (τ4+t2)+(c−d) (τ3+τ2)+(2d−c−b)τ1) 19
−2ip2(p−q)2q2 p2−q22
ei((c−d) (τ4+τ3+τ2+t2)+(2d−c−b)τ1) 20
i
2p(p−q)4q p2−q22
ei((c−d) (τ4+t2)+(b−d)τ3+(c−d)τ2+2(d−c)τ1) 21 ip2(p−q)2q2 p2−q22
ei((b−d) (τ4+τ3+t2)+(c−d)τ2+2(d−c)τ1) 22
−ip2(p−q)2q2 p2−q22
ei((b−d) (τ4+t2)+(c−d) (τ3+τ2)+2(d−c)τ1) 23
2ip3(p−q)4q3 ei((c−d) (τ4+τ3+τ2+t2)+2(d−c)τ1) 24
i
4(p−q)2 p2−q24
−i4(q+p)2 p2−q24
ei((d−b) (τ4+t2)+(d−c)τ3+(d−b)τ2+(2d−c−b)τ1) 25 S11
T able2.1− −continuation
Amplitude factor Exponential factor Term No.
ip2(p−q)2q2 p2−q22
−ip2q2(q+p)2 p2−q22
ei((d−b) (τ4+τ3+τ2+t2)+(2d−c−b)τ1) 26
i
2pq p2−q24
ei((d−b) (τ4+t2)+(d−c)τ3+(d−b)τ2+2(d−b)τ1) 27 2ip3q3 p2−q22
ei((d−b) (τ4+τ3+τ2+t2)+2(d−b)τ1) 28
i
2pq p2−q24
ei((d−b) (τ4+t2)+(d−c)τ3+(d−b)τ2+2(d−c)τ1) 29 2ip3q3 p2−q22
ei((d−b) (τ4+τ3+τ2+t2)+2(d−c)τ1) 30
−ip2q2(q+p)2 p2−q22
ei((d−b) (τ4+τ3+t2)+(d−c)τ2+2(d−b)τ1) 31
−ip2q2(q+p)2 p2−q22
ei((d−b) (τ4+τ3+t2)+(d−c)τ2+2(d−c)τ1) 32
i
2pq(q+p)4 p2−q22
−2ipq p2−q24
ei((d−b) (τ4+τ3+t2)+(d−c)τ2+(2d−c−b)τ1) 33 ip2q2(q+p)2 p2−q22
ei((d−b) (τ4+t2)+(d−c) (τ3+τ2)+2(d−b)τ1) 34 ip2q2(q+p)2 p2−q22
ei((d−b) (τ4+t2)+(d−c) (τ3+τ2)+2(d−c)τ1) 35
i
2pq(q+p)4 p2−q22
−2ipq p2−q24
ei((d−b) (τ4+t2)+(d−c) (τ3+τ2)+(2d−c−b)τ1) 36
−i2pq(q+p)4 p2−q22
ei((d−b) (τ4+t2)+(d−c)τ3+(d−b)τ2+2(b−d)τ1) 37
−2i(q+p)2 p2−q24
ei((d−b) (τ4+t2)+(d−c)τ3+(d−b)τ2+(−2d+c+b)τ1) 38
i
2pq p2−q24
ei((d−b) (τ4+t2)+(d−c)τ3+(d−b)τ2+2(c−d)τ1) 39
−2ip3q3(q+p)4 ei((d−b) (τ4+τ3+τ2+t2)+2(b−d)τ1) 40
−2ip2q2(q+p)2 p2−q22
ei((d−b) (τ4+τ3+τ2+t2)+(−2d+c+b)τ1) 41 2ip3q3 p2−q22
ei((d−b) (τ4+τ3+τ2+t2)+2(c−d)τ1) 42
−ip2q2(q+p)2 p2−q22
ei((d−b) (τ4+τ3+t2)+(d−c)τ2+2(b−d)τ1) 43
−ipq p2−q24
ei((d−b) (τ4+τ3+t2)+(d−c)τ2+(−2d+c+b)τ1) 44 ip2(p−q)2q2 p2−q22
ei((d−b) (τ4+τ3+t2)+(d−c)τ2+2(c−d)τ1) 45 ip2q2(q+p)2 p2−q22
ei((d−b) (τ4+t2)+(d−c) (τ3+τ2)+2(b−d)τ1) 46 ipq p2−q24
ei((d−b) (τ4+t2)+(d−c) (τ3+τ2)+(−2d+c+b)τ1) 47
−ip2(p−q)2q2 p2−q22
ei((d−b) (τ4+t2)+(d−c) (τ3+τ2)+2(c−d)τ1) 48 ip2(p−q)2q2 p2−q22
ei((d−c) (τ4+t2)+(d−b) (τ3+τ2)+2(d−b)τ1) 49 ip2(p−q)2q2 p2−q22
ei((d−c) (τ4+t2)+(d−b) (τ3+τ2)+2(d−c)τ1) 50
i
2p(p−q)4q p2−q22
−2ipq p2−q24
ei((d−c) (τ4+t2)+(d−b) (τ3+τ2)+(2d−c−b)τ1) 51
−ip2(p−q)2q2 p2−q22
ei((d−c) (τ4+τ3+t2)+(d−b)τ2+2(d−b)τ1) 52
−ip2(p−q)2q2 p2−q22
ei((d−c) (τ4+τ3+t2)+(d−b)τ2+2(d−c)τ1) 53
i
2pq p2−q24
−2ip(p−q)4q p2−q22
ei((d−c) (τ4+τ3+t2)+(d−b)τ2+(2d−c−b)τ1) 54
−2ipq p2−q24
ei((d−b) (τ4+t2)+(d−b)τ3+(d−c)τ2+2(d−b)τ1) 55
S12
T able2.1− −continuation
Amplitude factor Exponential factor Term No.
−2ipq p2−q24
ei((d−b) (τ4+t2)+(d−b)τ3+(d−c)τ2+2(d−c)τ1) 56
i
4(q+p)2 p2−q24
−i4(p−q)2 p2−q24
ei((d−b) (τ4+t2)+(d−b)τ3+(d−c)τ2+(2d−c−b)τ1) 57
−ip3q3 p2−q22
ei((d−c) (τ4+τ3+τ2+t2)+2(d−b)τ1) 58
−ip3q3 p2−q22
ei((d−c) (τ4+τ3+τ2+t2)+2(d−c)τ1) 59 ip2q2(q+p)2 p2−q22
−ip2(p−q)2q2 p2−q22
ei((d−c) (τ4+τ3+τ2+t2)+(2d−c−b)τ1) 60
−ip2q2(q+p)2 p2−q22
ei((d−c) (τ4+t2)+(d−b) (τ3+τ2)+2(b−d)τ1) 61 ip2(p−q)2q2 p2−q22
ei((d−c) (τ4+t2)+(d−b) (τ3+τ2)+2(c−d)τ1) 62
−ipq p2−q24
ei((d−c) (τ4+t2)+(d−b) (τ3+τ2)+(−2d+c+b)τ1) 63 ip2q2(q+p)2 p2−q22
ei((d−c) (τ4+τ3+t2)+(d−b)τ2+2(b−d)τ1) 64
−ip2(p−q)2q2 p2−q22
ei((d−c) (τ4+τ3+t2)+(d−b)τ2+2(c−d)τ1) 65 ipq p2−q24
ei((d−c) (τ4+τ3+t2)+(d−b)τ2+(−2d+c+b)τ1) 66
−2ipq p2−q24
ei((d−c) (τ4+t2)+(d−b)τ3+(d−c)τ2+2(b−d)τ1) 67
i
2p(p−q)4q p2−q22
ei((d−c) (τ4+t2)+(d−b)τ3+(d−c)τ2+2(c−d)τ1) 68
−2i(p−q)2 p2−q24
ei((d−c) (τ4+t2)+(d−b)τ3+(d−c)τ2+(−2d+c+b)τ1) 69
−2ip3q3 p2−q22
ei((d−c) (τ4+τ3+τ2+t2)+2(b−d)τ1) 70
2ip3(p−q)4q3 ei((d−c) (τ4+τ3+τ2+t2)+2(c−d)τ1) 71
−2ip2(p−q)2q2 p2−q22
ei((d−c) (τ4+τ3+τ2+t2)+(−2d+c+b)τ1) 72
p = cosξ q = sinξ
ξ = 1
2arctan 2πJ
ω1−ω2
Ω =
q
(ω1−ω2)2 + 4π2J2
(2.8)
Using the energy eigenvalues (in angular frequency units) of the four basis functions,
a = d = πJ
2 , b = −πJ
2 +Ω 2, c = −πJ
2 −Ω 2
(2.9)
and the timing conditions for removal ofJ−coupling effects at the centre of every data-chunk and for chemical shift refocusing at the beginning of the first data-chunk
S13
τ1 = t1
2 +δ1 = t1
2 + 2δ2+δ4, τ2 = t1
2 +δ2,
τ3 = δ3 = δ2+δ4, τ4 = t1
2 +δ4
(2.10)
the exponential factors can be simplified:
Table 2.2: Simplified terms
Amplitude factor Exponential factor No.
−i2pq(q+p)4 p2−q22
eiΩt22−iπJ t2−iΩδ4−2iΩδ2+2iπJ δ2 1 ip2q2(q+p)2 p2−q22
e−iΩt22−iπJ t2−iΩt21−2iΩδ4−2iΩδ2+2iπJ δ2 2
−2ip3q3(q+p)4 eiΩt22−iπJ t2−iΩδ2+2iπJ δ2 3
−ip2q2(q+p)2 p2−q22
e−iΩt22−iπJ t2−iΩt21−iΩδ4−iΩδ2+2iπJ δ2 4
−2i(q+p)2 p2−q24
eiΩt22−iπJ t2+iΩt21+2iπJ δ2 5 ipq p2−q24
e−iΩt22 −iπJ t2−iΩδ4+2iπJ δ2 6
−2ip2q2(q+p)2 p2−q22
eiΩt22−iπJ t2+iΩt21+iΩδ4+iΩδ2+2iπJ δ2 7
−ipq p2−q24
e−iΩt22−iπJ t2+iΩδ2+2iπJ δ2 8
i
2pq p2−q24
eiΩt22−iπJ t2+iΩt1+iΩδ4+2iΩδ2+2iπJ δ2 9
−ip2q2(p−q)2 p2−q22
e−iΩt22 −iπJ t2+iΩt12 +2iΩδ2+2iπJ δ2 10 2ip3q3 p2−q22
eiΩt22−iπJ t2+iΩt1+2iΩδ4+3iΩδ2+2iπJ δ2 11 ip2(p−q)2q2 p2−q22
e−iΩt22−iπJ t2+iΩt21+iΩδ4+3iΩδ2+2iπJ δ2 12
−2ipq p2−q24
e−iΩt22−iπJ t2−iΩt1−iΩδ4−2iΩδ2+2iπJ δ2 13
−ip2q2(q+p)2 p2−q22
eiΩt22 −iπJ t2−iΩt12 −2iΩδ2+2iπJ δ2 14 ip2q2(q+p)2 p2−q22
eiΩt22−iπJ t2−iΩt21−iΩδ4−3iΩδ2+2iπJ δ2 15
−2ip3q3 p2−q22
e−iΩt22−iπJ t2−iΩt1−2iΩδ4−3iΩδ2+2iπJ δ2 16
−2i(p−q)2 p2−q24
e−iΩt22−iπJ t2−iΩt21+2iπJ δ2 17
−ipq p2−q24
eiΩt22 −iπJ t2+iΩδ4+2iπJ δ2 18 ipq p2−q24
eiΩt22−iπJ t2−iΩδ2+2iπJ δ2 19
−2ip2(p−q)2q2 p2−q22
e−iΩt22−iπJ t2−iΩt21−iΩδ4−iΩδ2+2iπJ δ2 20
i
2p(p−q)4q p2−q22
e−iΩt22−iπJ t2+iΩδ4+2iΩδ2+2iπJ δ2 21 ip2(p−q)2q2 p2−q22
eiΩt22−iπJ t2+iΩt21+2iΩδ4+2iΩδ2+2iπJ δ2 22
−ip2(p−q)2q2 p2−q22
eiΩt22−iπJ t2+iΩt21+iΩδ4+iΩδ2+2iπJ δ2 23
S14
T able2.2− −continuation
Amplitude factor Exponential factor No.
2ip3(p−q)4q3 e−iΩt22−iπJ t2+iΩδ2+2iπJ δ2 24
i
4(p−q)2 p2−q24
−i4(q+p)2 p2−q24
e−iΩt22+iπJ t2−iΩt21+2iπJ t1+4iπJ δ4+6iπJ δ2 25 ip2(p−q)2q2 p2−q22
−ip2q2(q+p)2 p2−q22
e−iΩt22+iπJ t2−iΩt21+2iπJ t1−iΩδ4+4iπJ δ4−iΩδ2+6iπJ δ2 26
i
2pq p2−q24
e−iΩt22+iπJ t2−iΩt1+2iπJ t1−iΩδ4+4iπJ δ4−2iΩδ2+6iπJ δ2 27 2ip3q3 p2−q22
e−iΩt22+iπJ t2−iΩt1+2iπJ t1−2iΩδ4+4iπJ δ4−3iΩδ2+6iπJ δ2 28
i
2pq p2−q24
e−iΩt22+iπJ t2+2iπJ t1+iΩδ4+4iπJ δ4+2iΩδ2+6iπJ δ2 29 2ip3q3 p2−q22
e−iΩt22+iπJ t2+2iπJ t1+4iπJ δ4+iΩδ2+6iπJ δ2 30
−ip2q2(q+p)2 p2−q22
e−iΩt22+iπJ t2−iΩt21+2iπJ t1−2iΩδ4+4iπJ δ4−2iΩδ2+6iπJ δ2 31
−ip2q2(q+p)2 p2−q22
e−iΩt22 +iπJ t2+iΩt12 +2iπJ t1+4iπJ δ4+2iΩδ2+6iπJ δ2 32
i
2pq(q+p)4 p2−q22
−2ipq p2−q24
e−iΩt22+iπJ t2+2iπJ t1−iΩδ4+4iπJ δ4+6iπJ δ2 33 ip2q2(q+p)2 p2−q22
e−iΩt22+iπJ t2−iΩt21+2iπJ t1−iΩδ4+4iπJ δ4−iΩδ2+6iπJ δ2 34 ip2q2(q+p)2 p2−q22
e−iΩt22+iπJ t2+iΩt21+2iπJ t1+iΩδ4+4iπJ δ4+3iΩδ2+6iπJ δ2 35
i
2pq(q+p)4 p2−q22
−2ipq p2−q24
e−iΩt22 +iπJ t2+2iπJ t1+4iπJ δ4+iΩδ2+6iπJ δ2 36
−i2pq(q+p)4 p2−q22
e−iΩt22+iπJ t2+iΩδ4+2iΩδ2−2iπJ δ2 37
−2i(q+p)2 p2−q24
e−iΩt22+iπJ t2−iΩt21−2iπJ δ2 38
i
2pq p2−q24
e−iΩt22+iπJ t2−iΩt1−iΩδ4−2iΩδ2−2iπJ δ2 39
−2ip3q3(q+p)4 e−iΩt22 +iπJ t2+iΩδ2−2iπJ δ2 40
−2ip2q2(q+p)2 p2−q22
e−iΩt22+iπJ t2−iΩt21−iΩδ4−iΩδ2−2iπJ δ2 41 2ip3q3 p2−q22
e−iΩt22+iπJ t2−iΩt1−2iΩδ4−3iΩδ2−2iπJ δ2 42
−ip2q2(q+p)2 p2−q22
e−iΩt22+iπJ t2+iΩt21+2iΩδ2−2iπJ δ2 43
−ipq p2−q24
e−iΩt22+iπJ t2−iΩδ4−2iπJ δ2 44 ip2(p−q)2q2 p2−q22
e−iΩt22+iπJ t2−iΩt21−2iΩδ4−2iΩδ2−2iπJ δ2 45 ip2q2(q+p)2 p2−q22
e−iΩt22+iπJ t2+iΩt21+iΩδ4+3iΩδ2−2iπJ δ2 46 ipq p2−q24
e−iΩt22+iπJ t2+iΩδ2−2iπJ δ2 47
−ip2(p−q)2q2 p2−q22
e−iΩt22+iπJ t2−iΩt21−iΩδ4−iΩδ2−2iπJ δ2 48 ip2(p−q)2q2 p2−q22
eiΩt22+iπJ t2−iΩt21+2iπJ t1−iΩδ4+4iπJ δ4−3iΩδ2+6iπJ δ2 49 ip2(p−q)2q2 p2−q22
eiΩt22+iπJ t2+iΩt21+2iπJ t1+iΩδ4+4iπJ δ4+iΩδ2+6iπJ δ2 50
i
2p(p−q)4q p2−q22
−2ipq p2−q24
eiΩt22+iπJ t2+2iπJ t1+4iπJ δ4−iΩδ2+6iπJ δ2 51
−ip2(p−q)2q2 p2−q22
eiΩt22+iπJ t2−iΩt21+2iπJ t1+4iπJ δ4−2iΩδ2+6iπJ δ2 52
−ip2(p−q)2q2 p2−q22
eiΩt22+iπJ t2+iΩt21+2iπJ t1+2iΩδ4+4iπJ δ4+2iΩδ2+6iπJ δ2 53
S15
T able2.2− −continuation
Amplitude factor Exponential factor No.
i
2pq p2−q24
−2ip(p−q)4q p2−q22
eiΩt22+iπJ t2+2iπJ t1+iΩδ4+4iπJ δ4+6iπJ δ2 54
−2ipq p2−q24
e−iΩt22+iπJ t2−iΩt21+2iπJ t1−2iΩδ4+4iπJ δ4−2iΩδ2+6iπJ δ2 55
−2ipq p2−q24
e−iΩt22+iπJ t2+iΩt21+2iπJ t1+4iπJ δ4+2iΩδ2+6iπJ δ2 56
i
4(q+p)2 p2−q24
−i4(p−q)2 p2−q24
e−iΩt22+iπJ t2+2iπJ t1−iΩδ4+4iπJ δ4+6iπJ δ2 57
−ip3q3 p2−q22
eiΩt22+iπJ t2+2iπJ t1+4iπJ δ4−iΩδ2+6iπJ δ2 58
−ip3q3 p2−q22
eiΩt22+iπJ t2+iΩt1+2iπJ t1+2iΩδ4+4iπJ δ4+3iΩδ2+6iπJ δ2 59 ip2q2(q+p)2 p2−q22
−ip2(p−q)2q2 p2−q22
eiΩt22+iπJ t2+iΩt21+2iπJ t1+iΩδ4+4iπJ δ4+iΩδ2+6iπJ δ2 60
−ip2q2(q+p)2 p2−q22
eiΩt22+iπJ t2+iΩt21+iΩδ4+iΩδ2−2iπJ δ2 61 ip2(p−q)2q2 p2−q22
eiΩt22 +iπJ t2−iΩt12 −iΩδ4−3iΩδ2−2iπJ δ2 62
−ipq p2−q24
eiΩt22+iπJ t2−iΩδ2−2iπJ δ2 63 ip2q2(q+p)2 p2−q22
eiΩt22+iπJ t2+iΩt21+2iΩδ4+2iΩδ2−2iπJ δ2 64
−ip2(p−q)2q2 p2−q22
eiΩt22+iπJ t2−iΩt21−2iΩδ2−2iπJ δ2 65 ipq p2−q24
eiΩt22 +iπJ t2+iΩδ4−2iπJ δ2 66
−2ipq p2−q24
eiΩt22+iπJ t2+iΩt1+iΩδ4+2iΩδ2−2iπJ δ2 67
i
2p(p−q)4q p2−q22
eiΩt22+iπJ t2−iΩδ4−2iΩδ2−2iπJ δ2 68
−2i(p−q)2 p2−q24
eiΩt22+iπJ t2+iΩt21−2iπJ δ2 69
−2ip3q3 p2−q22
eiΩt22 +iπJ t2+iΩt1+2iΩδ4+3iΩδ2−2iπJ δ2 70
2ip3(p−q)4q3 eiΩt22+iπJ t2−iΩδ2−2iπJ δ2 71
−2ip2(p−q)2q2 p2−q22
eiΩt22+iπJ t2+iΩt21+iΩδ4+iΩδ2−2iπJ δ2 72
Cosine modulated terms
Out of these 72 terms 48 terms can be combined into 24 cosine modulated terms using the complex exponential identity:
eiφ + e−iφ = 2 cos (φ) (2.11)
These terms are purely imaginary which means that since
F+ = Fx + iFy (2.12)
they represent y-magnetization and will appear as in-phase multiplets in the spectra. These cosine modulated terms can further be decomposed into nine term groups listed in Table 2.3.
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In Table 2.3, the term groups are separated into an amplitude factor and four exponential modulation factors, which represent the offset 12(ω1 +ω2), the evolution of J−coupling and chemical shift Ω during the evolution times t1 andt2 and a constant phase factor depending on Ω,δ2 andδ4. Note that the density matrix calculation was performed with an offset set to zero (12(ω1 +ω2) = 0). The classification is performed depending on the frequency of the coherence transfer between the two protons and which of the four pulses in the PEPSIE pulse sequence causes this transfer (Table 2.4).
Table 2.3: Cosine modulated terms
Frequency modulation factor for all terms: e±(iπJ(t2−2δ2))·e2i(ω1+ω2)(t1+t2) Term
Terms Amplitude Chem. Shift Constant phase
group factor modulation factor
1 5, 38 −i(q−p)4(q+p)6 e±iΩ2(t2+t1)
1 17, 69 −i(q−p)6(q+p)4 e∓iΩ2(t2+t1)
2 9, 39 ipq p2−q24
e±iΩ2(t2+ 2t1) e±iΩ(2δ2+δ4) 13, 67 −ipq p2−q24
e∓iΩ2(t2+ 2t1) e∓iΩ(2δ2+δ4)
3 1, 37 −ipq(q+p)4 p2−q22
e±iΩt22 e∓iΩ(2δ2+δ4) 21, 68 ipq(p−q)4 p2−q22
e∓iΩt22 e±iΩ(2δ2+δ4)
4 6, 66, 8, 63 2ipq p2−q24
e∓iΩt22
e∓iΩδ4−e±iΩδ2 18, 44, 19, 47 2ipq p2−q24
e±iΩt22
e∓iΩδ2−e±iΩδ4
5 2, 64, 4, 61 ip2q2(q+p)2 p2−q22
e∓iΩ2(t2+t1)
e∓iΩ(δ2+δ4)−e∓2iΩ(δ2+δ4) 22, 45, 23, 48 ip2q2(q−p)2 p2−q22
e±iΩ2(t2+t1)
e±2iΩ(δ2+δ4)−e±iΩ(δ2+δ4)
6 10, 65, 12, 62 ip2q2(p−q)2 p2−q22
e∓iΩ2(t2−t1)
e±iΩ(3δ2+δ4)−e±2iΩδ2 14, 43, 15, 46 ip2q2(q+p)2 p2−q22
e±iΩ2(t2−t1)
e∓2iΩδ2−e∓iΩ(3δ2+δ4)
7 7, 41 −2ip2q2(q+p)2 p2−q22
e±iΩ2(t2+t1) e±iΩ(δ2+δ4) 20, 72 −2ip2q2(p−q)2 p2−q22
e∓iΩ2(t2+t1) e∓iΩ(δ2+δ4)
8 11, 42 2ip3q3 p2−q22
e±iΩ2(t2+ 2t1) e±iΩ(3δ2+2δ4) 16, 70 −2ip3q3 p2−q22
e∓iΩ2(t2+ 2t1) e∓iΩ(3δ2+2δ4)
9 3, 40 −2ip3q3(p+q)4 e±iΩt22 e∓iΩδ2
24, 71 2ip3q3(p−q)4 e∓iΩt22 e±iΩδ2
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Table2.4:Cosinemodulatedterms:Assignment GroupTermsAssignmentCoherencetransfer frequencycausingpulse 15,17,38,69desiredpeaksNoNo 29,13,39,67phase-modulated doubletransfer180◦-pulsefirstecho artifacts¢ral90◦-pulse 31,21,37,68centralartifactsingletransfer180◦-pulsefirstecho 46,8,18,19, centralartifactsingletransfer1st.or2nd.180◦- 44,47,63,66pulsesecondecho 52,4,22,23,phase-modulated doubletransfer180◦-pulsefirstecho& 45,48,61,64artifacts1st.or2nd.180◦-pulsesecondecho 610,14,43,65phase-modulated tripletransfer180◦-pulsefirstecho,central90◦-pulse& 12,15,46,62artifacts1st.or2nd.180◦-pulsesecondecho 77,20,41,72phase-modulated doubletransfer1st.&2nd.180◦-pulse artifactssecondecho 811,16,42,70phase-modulated fourfoldtransferall180◦-pulses artifacts¢ral90◦-pulse 93,24,40,71centralartifacttripletransferall180◦-pulses
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Evolution of the amplitude factors with increasing degree of strong coupling
For illustration, how the amplitudes of the cosine modulated terms in table 2.3 evolve with increasing degree of strong coupling, their amplitude factors are plotted against the relation of shift difference ∆νand coupling constantJ. In all plots the constant phase factor in table 2.3 is considered, whereas Ω was calculated from ∆νJ using the proton coupling constant of 2,3-dibromothiopheneJ = 5.75 Hz. Figure 2.2 shows the plots of the term groups contributing to the central artifact (3,4and9) in comparison to the desired in-phase peaks (term group1).
1 5 1 4 1 3 1 2 1 1 1 0 9 8 7 6 5 4 3 2 1 0
0 . 0 0 . 5 1 . 0 1 . 5 2 . 0
amplitude / a.u.
∆ν/ J
D e s i r e d i n - p h a s e p e a k s T e r m g r o u p 3
T e r m g r o u p 9 T e r m g r o u p 4
S u m o f g r o u p s 3 , 4 a n d 9
Figure 2.2: Plot of the amplitude factors of the term groups contributing to the central artifact (3,4and9in Table 2.3) in comparison to the desired in-phase peaks (term group1, blue line) against the relation of shift difference ∆νand coupling constantJ. The black line is the sum of the terms contributing to the central artifact.
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1 5 1 4 1 3 1 2 1 1 1 0 9 8 7 6 5 4 3 2 1 0 - 0 . 2
0 . 0 0 . 2 0 . 4 0 . 6 0 . 8 1 . 0 1 . 2 1 . 4 1 . 6 1 . 8 2 . 0
amplitude / a.u.
∆ν/ J
D e s i r e d i n - p h a s e p e a k s ( s u m m e d a m p l i t u d e ) T e r m g r o u p 2
T e r m g r o u p 5 T e r m g r o u p 6 T e r m g r o u p 7 T e r m g r o u p 8
Figure 2.3: Plot of the amplitude factors of the term groups2,5,6, 7and8in Table 2.3 in comparison to the desired in-phase peaks (term group1, blue line) against the relation of shift difference ∆ν and coupling constantJ.
Figure 2.3 shows the plots of the term groups 2, 5, 6, 7and 8, which lead to artifacts with phase distortions, in comparison to the desired in-phase peaks. Theses artifacts are not visible in the pure shift spectra of 2,3-dibromothiophene. However, these are potentially observable in other systems or in pure shift spectra obtained with other acquisition parameters, since their amplitudes depends on shift difference Ω, theJ−coupling constant and the time constantsδ2
andδ4as well.
Exponential modulated terms
The remaining 24 terms in table 2.2 have complex exponential modulation and can be decom-posed into a real and an imaginary part, thus they represent mixed x- and y-magnetization. This would lead to a phase-modulated multiplet appearance. All these terms exhibitJ−coupling evo-lution duringt1and are listed in table 2.5 The terms25and57have amplitude factors with two components, which do not vanish in the weak coupling case (p = 1 andq = 0). However, the first component cancels the second one in the weakly coupled case. If strong coupling is present this is not achieved. Thus we assume that these are the anti-phase terms of equation 1.12 in chapter 1.2. Furthermore there are additional terms with polarisation transfer as a result of strong coupling.
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Table 2.5: Exponential modulated terms
Amplitude factor Exponential factor No.
i
4(p−q)2 p2−q24
−i4(q+p)2 p2−q24
e−iΩt22 +iπJ t2−iΩt12 +2iπJ t1+4iπJ δ4+6iπJ δ2 25 ip2(p−q)2q2 p2−q22
−ip2q2(q+p)2 p2−q22
e−iΩt22+iπJ t2−iΩt21+2iπJ t1−iΩδ4+4iπJ δ4−iΩδ2+6iπJ δ2 26
i
2pq p2−q24
e−iΩt22+iπJ t2−iΩt1+2iπJ t1−iΩδ4+4iπJ δ4−2iΩδ2+6iπJ δ2 27 2ip3q3 p2−q22
e−iΩt22+iπJ t2−iΩt1+2iπJ t1−2iΩδ4+4iπJ δ4−3iΩδ2+6iπJ δ2 28
i
2pq p2−q24
e−iΩt22 +iπJ t2+2iπJ t1+iΩδ4+4iπJ δ4+2iΩδ2+6iπJ δ2 29 2ip3q3 p2−q22
e−iΩt22+iπJ t2+2iπJ t1+4iπJ δ4+iΩδ2+6iπJ δ2 30
−ip2q2(q+p)2 p2−q22
e−iΩt22+iπJ t2−iΩt21+2iπJ t1−2iΩδ4+4iπJ δ4−2iΩδ2+6iπJ δ2 31
−ip2q2(q+p)2 p2−q22
e−iΩt22+iπJ t2+iΩt21+2iπJ t1+4iπJ δ4+2iΩδ2+6iπJ δ2 32
i
2pq(q+p)4 p2−q22
−2ipq p2−q24
e−iΩt22+iπJ t2+2iπJ t1−iΩδ4+4iπJ δ4+6iπJ δ2 33 ip2q2(q+p)2 p2−q22
e−iΩt22+iπJ t2−iΩt21+2iπJ t1−iΩδ4+4iπJ δ4−iΩδ2+6iπJ δ2 34 ip2q2(q+p)2 p2−q22
e−iΩt22+iπJ t2+iΩt21+2iπJ t1+iΩδ4+4iπJ δ4+3iΩδ2+6iπJ δ2 35
i
2pq(q+p)4 p2−q22
−2ipq p2−q24
e−iΩt22+iπJ t2+2iπJ t1+4iπJ δ4+iΩδ2+6iπJ δ2 36 ip2(p−q)2q2 p2−q22
eiΩt22+iπJ t2−iΩt21+2iπJ t1−iΩδ4+4iπJ δ4−3iΩδ2+6iπJ δ2 49 ip2(p−q)2q2 p2−q22
eiΩt22+iπJ t2+iΩt21+2iπJ t1+iΩδ4+4iπJ δ4+iΩδ2+6iπJ δ2 50
i
2p(p−q)4q p2−q22
−2ipq p2−q24
eiΩt22+iπJ t2+2iπJ t1+4iπJ δ4−iΩδ2+6iπJ δ2 51
−ip2(p−q)2q2 p2−q22
eiΩt22+iπJ t2−iΩt21+2iπJ t1+4iπJ δ4−2iΩδ2+6iπJ δ2 52
−ip2(p−q)2q2 p2−q22
eiΩt22+iπJ t2+iΩt21+2iπJ t1+2iΩδ4+4iπJ δ4+2iΩδ2+6iπJ δ2 53
i
2pq p2−q24
−2ip(p−q)4q p2−q22
eiΩt22+iπJ t2+2iπJ t1+iΩδ4+4iπJ δ4+6iπJ δ2 54
−2ipq p2−q24
e−iΩt22+iπJ t2−iΩt21+2iπJ t1−2iΩδ4+4iπJ δ4−2iΩδ2+6iπJ δ2 55
−2ipq p2−q24
e−iΩt22 +iπJ t2+iΩt12 +2iπJ t1+4iπJ δ4+2iΩδ2+6iπJ δ2 56
i
4(q+p)2 p2−q24
−i4(p−q)2 p2−q24
e−iΩt22+iπJ t2+2iπJ t1−iΩδ4+4iπJ δ4+6iπJ δ2 57
−ip3q3 p2−q22
eiΩt22+iπJ t2+2iπJ t1+4iπJ δ4−iΩδ2+6iπJ δ2 58
−ip3q3 p2−q22
eiΩt22+iπJ t2+iΩt1+2iπJ t1+2iΩδ4+4iπJ δ4+3iΩδ2+6iπJ δ2 59 ip2q2(q+p)2 p2−q22
−ip2(p−q)2q2 p2−q22
eiΩt22 +iπJ t2+iΩt12 +2iπJ t1+iΩδ4+4iπJ δ4+iΩδ2+6iπJ δ2 60
To estimate the consequences for the observation, let us discuss the behaviour based on term 25. The evolution of anti-phase coherences into detectable in-phase coherence is sine-modulated with theJ−coupling constant andt2. The classical COSY-experiment, which shows anti-phase multiplets in the direct and indirect dimension, teaches us, that a sine-modulated antiphase FID, which starts at zero intensity fort2 = 0 requires a minimum acquisition of data points to get enough signal intensity. In pure shift experiments, which were aquired with the interferogram-based aquisition mode, the duration of one FID-chunk is comparably low (≤ 20 ms) to keep J−coupling evolution at minimum. Subsequently, the effect of the anti-phase terms on the PEPSIE pure shift spectra can be neglected. Note, that in systems with comparably large
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coupling constants these anti-phase artifacts might be visible. This context is exemplary illus-trated in Figure 2.4 for the term 25in Table 2.5. The plot shows the evolution of the pure amplitude factor of anti-phase term25with increasing degree of strong coupling. Comparing to the amplitude of the desired in-phase signals (blue line) the pure amplitude of term25(black) is low. If an aquisition time t2 = 20 ms of one data-chunk and the J−coupling constant of 2,3-dibromothiophene of 5.75 Hz is considered, the amplitude is further decreased by weighting with the sine-modulation factor (see equation 1.12). Assuming aJ−coupling constant of 15 Hz higher amplitude values can be expected, but they are negligible compared to the amplitude of the desired in-phase signals.
1 5 1 4 1 3 1 2 1 1 1 0 9 8 7 6 5 4 3 2 1 0
- 0 . 2 0 . 0 0 . 2 0 . 4 0 . 6 0 . 8 1 . 0
absolute amplitude / a.u.
∆ν/ J T e r m 2 5 : p u r e a m p l i t u d e T e r m 2 5 : t2= 2 0 m s , J = 5 . 7 5 H z T e r m 2 5 : t2= 2 0 m s , J = 1 5 H z d e s i r e d i n - p h a s e p e a k s
Figure 2.4: Plot of the amplitude factor of term25in comparison to the desired in-phase peaks (term group1, blue line) against the relation of shift difference ∆νand coupling constantJ. The black line is the evolution of the pure amplitude factor at the beginning of signal detection (zero detectable intensity). The green and the orange plots show the potentially detectable intensity after 20 ms aquisition time for the case of 2,3-dibromothiophene (J = 5.75 Hz) and the case of a comparably large proton-protonJ-coupling constant of 15 Hz.
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3 PSYCHE, TSE-PSYCHE and simulated spectra with increasing