Monodeuterated 



CH3-O-C(=O)H


 





 





 






Deuterium


Nuclear Quadrupole Coupling Constants


in Monodeuterated Methyl Formate


 








 








 








Deuterium nqcc tensors in monodeuterated methyl formate were calculated here on ropt structures given by MP2/aug-cc-pVTZ(G03) [this work] and MP2/cc-pVQZ [1] optimizations, and on an reSE structure derived by Demaison et al. [2].  These nqcc's are compared with the eperimental values [3 - 5] in Tables 1 - 3.  Structure parameters are compared in Table 4.

 








In Tables 1 - 3, RMS is the root mean square difference between calculated and experimental diagonal nqcc's (percentage of the average of the magnitudes of the experimental nqcc's).  RSD is the calibration residual standard deviation for the B3LYP/6-31G(df,3p) model for calculation of the deuterium nqcc's, which may be taken as an estimate of the uncertainties in the calculated nqcc's.

Subscripts a,b,c refer to the principal axes of the inertia tensor; x,y,z to the principal axes of the nqcc tensor.  The nqcc y-axis is chosen coincident with the inertia c-axis, these are perpendicular to the molecular symmetry plane.  Ø (degrees) is the angle between its subscripted parameters.  ETA = (Xxx - Xyy)/Xzz.

 








 








   





Table 1.  Deuterium nqcc's in CH3-O-C(=O)D (kHz).  Calculation was made on the (1) MP2/aug-cc-pVTZ(G03) and (2) MP2/cc-pVQZ ab initio structures, and on the (3) reSE structure.
   






Calc. ropt(1) Calc. ropt(2) Calc. reSE Expt. [3,4]
   





Xaa - 22.1 - 22.3 - 20.7 - 23.2(15)

Xbb 110.9 111.8 109.7 107.2(18)

Xcc - 88.8 - 89.5 - 89.1 - 84.0

|Xab| 110.3 111.2 111.6


 





RMS 3.5 (4.9 %) 4.2 (5.8 %) 3.6 (5.0 %)


RSD 1.1 (0.9 %) 1.1 (0.9 %) 1.1 (0.9 %)


 





Xxx - 84.4 - 85.1 - 84.7


Xyy - 88.8 - 89.5 - 89.1


Xzz 173.2 174.6 173.8


ETA 0.025 0.025 0.025


Øz,a 60.54 60.55 60.15


Øa,CD 60.95 60.96 60.47


Øz,CD   0.40   0.41   0.32


 






 








 








   









Table 2.  Deuterium nqcc's in the Cs configuration of CH2D-O-C(=O)H (kHz).  Calculation was made on the (1) MP2/aug-cc-pVTZ(G03) and (2) MP2/cc-pVQZ ab initio structures, and on the (3) reSE structure.
   











Calc. ropt(1)
Calc. ropt(2)
Calc. reSE
Expt. [5]
   









Xaa
165.7
167.8
170.4
154.8

Xbb
- 64.3
- 65.1
- 66.2
- 61.0(19)

Xcc - 101.4 - 102.7 - 104.1
- 93.8(20)

|Xab|
  73.9
  74.7
  75.7



 









RMS
7.9 (7.7 %)
9.4 (9.1 %)
11.2 (10.9 %)



RSD
1.1 (0.9 %)
1.1 (0.9 %)
  1.1 (0.9 %)



 









Xxx
- 86.0
- 87.1
- 88.4



Xyy - 101.4 - 102.7 - 104.1



Xzz
187.4
189.7
192.5



ETA
0.082
0.082
0.082



Øz,a
16.36
16.34
16.30



Øa,CD
16.79
16.78
16.63



Øz,CD
  0.43
  0.44
  0.33



 










 








 








   









Table 3.  Deuterium nqcc's in the C1 configuration of CH2D-O-C(=O)H (kHz).  Calculation was made on the (1) MP2/aug-cc-pVTZ(G03) and (2) MP2/cc-pVQZ ab initio structures, and on the (3) reSE structure.
   











Calc. ropt(1)
Calc. ropt(2)
Calc. reSE
Expt. [5]
   









Xaa
- 83.4
- 84.7
- 83.8
- 80.0

Xbb
    2.2
    2.8
    3.0
    3.1(11)

Xcc
  81.2
  81.8
  80.8
  76.9(13)

|Xab|
  21.6 *
  21.7 *
  21.0 *



|Xac|
  45.3
  45.5
  44.5



|Xbc|
126.1
128.0
126.7



 









RMS
3.2 (6.0 %)
3.9 (7.4 %)
3.2 (6.0 %)



RSD
1.1 (0.9 %)
1.1 (0.9 %)
1.1 (0.9 %)



 









Xxx
- 82.1
- 83.2
- 82.2



Xyy - 100.8 - 102.2 - 101.0



Xzz
183.0
185.4
183.2



ETA
0.102
0.102
0.103



Øz,CD
  0.40
  0.39
  0.38



 










 








* the algebraic sign of the product XabXacXbc is positive.

 








 



Table 4.  CH3-O-C(=O)H.  Structure parameters:  (1) MP2/aug-cc-pVTZ(G03) and (2) MP2/cc-pVQZ [1] optimized structures, and (3) reSE [2] (Å and degrees).  These structures are given here in Z-matrix format.
 





ropt(1) ropt(2)    reSE





O(1)C(3) 1.4389 1.4344 1.4341(5)
O(1)C(2)
 1.3403 1.3370 1.3345(4)
CH(6) 1.0837 1.0817 1.0793(10)
CH(7,8) 1.0872 1.0851 1.0871(3)
CH(5)
 1.0934 1.0922 1.0930(5)
C=O 1.2079 1.2035 1.2005(5)
COC 113.97 114.0 114.32(4)
OCH(6) 105.44 105.5 106.05(16)
Click on image to enlarge. OCH(7,8) 110.16 110.3 110.19(2)
OCH(5) 109.24 109.2 109.60(5)

OCO 125.60 125.6 125.50(5)

H(7)COC   60.32   60.3   60.28(3)







 








 








[1] M.L.Senet, M.Villa, F.J.Meléndez, and R.Domínguez-Gómez, Ap.J. 627, 567(2005).

[2] J.Demaison, L.Margulès, I.Kleiner, and A.G.Császár, J.Mol.Spectrosc. 259,70(2010).

[3] M.Carvajal, L.Margulès, T.Huet, J.Demaison, I.Kleiner, H.Møllendal, B.Tercero, N.Marcelino, and J.Cernicharo, Abstract/Poster D14, 21st Colloquium on High Resolution Molecular Spectroscopy, Castellammare di Stabia, Italy, 2009.
[4] L.Margulès, T.Huet, J.Demaison, M.Carvajal, I.Kleiner, H.Møllendal, B.Tercero, N.Marcelino, and J.Cernicharo, ApJ 714,1120(2010).

[5] L.Margulès, L.H.Coudert, H.Møllendal, J.-C.Guillemin, T.Huet, and R.Janečkovà, J.Mol.Spectrosc. 254,55(2009).

 








 








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Last Modified 8 Dec 2009