germanium quadrupole coupling in the rotational spectrum of (ch 3 ) 3 73 ge 35 cl juliane fritzsche...

Germanium quadrupole coupling in the rotational spectrum of (CH3)3

73Ge35Cl

Juliane Fritzschea

Jens-Uwe Grabowa Melanie Schnellb

61st International Symposium on Molecular Spectroscopy, Columbus (OH)

aUniversität Hannover

Institut für Physikalische Chemie und Elektrochemie

Callinstraße 3-3a, D-30167 Hannover

bFritz-Haber-Institut der Max-Planck-Gesellschaft

Abteilung Molekülphysik

Faradayweg 4-6, D-14195 Berlin

(CH3)3GeCl


Chlorine

Germanium

Hydrogen

Carbon

1



(CH3)3GeCl


Chlorine

Germanium

Hydrogen

Carbon

2



Isotopomers

abundance nuclear spin

Ge Cl total Ge Cl

(CH3)370Ge35Cl 0,2055 0,754 0,1549 0 3/2

(CH3)370Ge37Cl 0,2055 0,246 0,0506 0 3/2

(CH3)372Ge35Cl 0,2737 0,754 0,2025 0 3/2

(CH3)372Ge37Cl 0,2737 0,246 0,0673 0 3/2

(CH3)374Ge35Cl 0,3674 0,754 0,2770 0 3/2

(CH3)374Ge37Cl 0,3674 0,246 0,0904 0 3/2

(CH3)376Ge35Cl 0,0767 0,754 0,0578 0 3/2

(CH3)376Ge37Cl 0,0767 0,246 0,0189 0 3/2

(CH3)373Ge35Cl 0,0767 0,754 0,0578 9/2 3/2

(CH3)373Ge37Cl 0,0767 0,246 0,0189 9/2 3/2

61st International Symposium on Molecular Spectroscopy, Columbus (OH) 3



Characteristics of the rotational spectrum of (CH3)3GeCl

J+1,K J,K-transition frequency area

37Cl-isotopomers

17 groups due to internal rotation

(K=0, K=1)

35Cl-isotopomers

5 Ge-isotopomers


(K=0, K=1)

5 Ge-isotopomers

Cl-HFSCl-HFS




70 72 73 74 76 70 72 73 74 76

Internal rotation




• determined in previous investigation of

72Ge- and 74Ge-isotopomers

• combination of permutation-inversion

(PI) group theory and multidimensional

high-barrier tunneling formalism

characteristic pattern

A1 I2 I1 I4 E2 I3

Stat. weights 24 64 32 32 8 16

Characteristic patternJ0

AA

E2

A

EA,AEEE

EEEEEA,EAE,AEEEAA,AEA,AAE

AAA

A1

E2+I3A1 I1+I4I2

E

I4 I3I1I2

Top 1

Top 2

Top 3


J: 2 1, K = 0 7958.3 MHz7959.6

6



Spectrum (CH3)3GeCl

0

1

2

3

4

5

6

7

8

7947 7949 7951 7953 7955 7957 7959 7961 7963 7965 7967 7969 7971 7973 7975 7977

frequency / MHz

inte

nsi

ty /

mV

rms


70Ge

1-3

K=

0 5-

5 K

=0

3-5

K=

1

3-3

K=

1

5-5

K=

15-

3 K

=0

1-1

K=

05-

7 K

=0

3-5

K=

01-

3 K

=1

5-3

K=

1

5-7

K=

1

72Ge

1-3

K=

0 5-

5 K

=0

3-5

K=

1

3-3

K=

1

5-5

K=

15-

3 K

=0

1-1

K=

05-

7 K

=0

3-5

K=

01-

3 K

=1

5-3

K=

1

5-7

K=

1

1-3

K=

1

3-3

K=

0

1-1

K=

1

74Ge

1-3

K=

0 5-

5 K

=0

3-5

K=

1

3-3

K=

1

5-5

K=

15-

3 K

=0

1-1

K=

05-

7 K

=0

3-5

K=

01-

3 K

=1

5-3

K=

1 5-

7 K

=1

1-3

K=

1

3-3

K=

0

1-1

K=

1

76Ge

3-3

K=

1

5-5

K=

15-

3 K

=0

1-1

K=

05-

7 K

=0

3-5

K=

01-

3 K

=1

5-3

K=

1

5-7

K=

1

1-3

K=

1

3-3

K=

0

1-1

K=

1

3-1

K=

0

7

J=2←1



(CH3)373GeCl


Chlorine

Germanium

Hydrogen

Carbon

8



Characteristics of the rotational spectrum of (CH3)3

73GeCl

J+1,K J,K-transition frequency range

37Cl-isotopomers 35Cl-isotopomers


(K=0, K=1)

5 Ge-isotopomers

Cl-HFS

70 72 73 74 76

Ge-HFS

5 Ge-isotopomers

Cl-HFS

70 72 73 74 76

Ge-HFS


(K=0, K=1)




Spectrum (CH3)3GeCl

0

1

2

3

4

5

6

7

8

7947 7949 7951 7953 7955 7957 7959 7961 7963 7965 7967 7969 7971 7973 7975 7977

frequency / MHz

inte

nsi

ty /

mV

rms


J=2←1



1-3

K=

0 5-

5 K

=0

3-5

K=

1

3-3

K=

1

5-5

K=

15-

3 K

=0

1-1

K=

05-

7 K

=0

3-5

K=

01-

3 K

=1

5-3

K=

1

5-7

K=

1

1-3

K=

1

3-3

K=

0

1-1

K=

1

73Ge

0

0,01

0,02

0,03

0,04

0,05

7952,9 7953,1 7953,3 7953,5 7953,7 7953,9

A1I2I1I4


(CH3)373GeCl

11



frequency / MHz

inte

nsit

y / m

Vrm

s

J=2←1

• which transition?

• several calculations by varying the value of eQq (Ge) using „sym2qs“

• only one reasonable assignment F1´,F´← F1,F =

5/2,7←5/2,6

Proceeding




• due to relative magnitude of 2nd order effects two fitting results reproduce

experimental observation F1´,F´← F1,F 5/2,7←5/2,6

eQq(Ge)= -16.01 MHz eQq(Ge)= -34.61 MHz

• requires unusual small field gradient q

at 73Ge nucleus

• no corresponding other hyperfine

components observed at predicted

position

• large nuclear quadrupole moment Q of 73Ge

• consistent with plausible field

gradient q at 73Ge nucleus

• consistent with F1‘,F‘← F1,F

7/2,6← 5/2,6 components at

7960.07 MHz

(CH3)373Ge35Cl

B / MHz 1990.549113(23)*

DJ / kHz 0.3121(0)*

eQq / MHz (Cl) -40.0656(41)*

eQq / MHz (Ge) -34.61

Results and Outlook




• measurement of J=1←0 (adapt antennas to low frequencies)

• „only“ 29 quadrupole components: less overlap, easier assigment

Next steps

Acknowledgement

• mechanical workshop: H. Bieder, W. Becker, W. Egly

• electronical workshop: W. Rogge

• Deutsche Forschungsgemeinschaft

• Land Niedersachsen




Internal rotation




27333 GCCC

E, 2C3, 3σv

6 symmetry elements

G162

HR: rotation of 1 single CH3-groupHA: anti-geared rotation of 2 CH3-groupsHG: geared rotation of 2 CH3-groupsHE: rotation of 3 CH3-groups with the same senseHL: rotation of 3 CH3-groups with different sense

5 topologically inequivalent tunneling pathways:


sixfold degenerateI1 –I4

twofold degenerateE

non-degenerateA

Tunneling Hamiltonian matrix for K=0

characteristic pattern

Internal rotationInstitut für Physikalische

Chemie und Elektrochemie Callinstraße 3-3a, D-30167 Hannover

Experimental setup




flow rate reaction source




germanium quadrupole coupling in the rotational spectrum of (ch 3 ) 3 73 ge 35 cl juliane fritzsche...

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