H2C=P-CN























 








Nitrogen


Nuclear Quadrupole Coupling Constants


in P-Cyanophosphaethene


 








 








 








Calculation of the nitrogen nqcc tensor in P-cyanophosphaethene was made here on molecular structures given by MP2/6-311+G(3df,3pd) and MP2/aug-cc-pVTZ optimization, each corrected with approximate equilibrium CN bond length.  These nqcc's are given in Table 1.  Structure parameters are given in Z-matrix format in Table 2,  rotational constants in Table 3, dipole moments and quartic centrifugal distortion constants in Table 4.


 








In Table 1, subscripts a,b,c refer to the principal axes of the inertia tensor, subscripts x,y,z to the principal axes of the nqcc tensor.  ETA = (Xxx - Xyy)/Xzz.  Ø (degrees) is the angle between its subscripted parameters.


RSD is the residual standard deviation of calibration of the B3PW91/6-311+G(df,pd) model for calculation of the efg's/nqcc's.

 








 








 








Table 1. Nitrogen nqcc's in H2C=P-CN (MHz).  Calculation was made here on molecular structures given by (1) MP2/6-311+G(3df,3pd) and (2) MP2/aug-cc-pVTZ optimization, each with approximate re(CN).

 










Calc (1)

Calc (2)

Expt

 








Xaa -
4.274
-
4.248




Xbb
1.743

1.734




Xcc
2.531

2.514




Xab
1.690

1.709













RSD
0.030 (1.3 %)
0.030 (1.3 %)












Xxx
2.185

2.188




Xyy
2.531

2.514




Xzz -
4.716
-
4.702




ETA
0.073

0.069




Øz,a
16.66

14.87




Øa,CN
13.22

13.48




Øz,CN
  1.44

  1.39













   








 








 



Table 2.  H2C=P-CN.  Optimized structure parameters (Å and degrees).  Approximate re(CN) bond lengths are given in parentheses.






 P
 C,1,B1
 H,2,B2,1,A1
 H,2,B3,1,A2,3,D1,0
 C,1,B4,2,A3,3,D2,0
 N,5,B5,1,A4,2,D3,0







MP2/6-311+G(3df,3pd)
MP2/aug-cc-pVTZ






 B1=1.66504944
 B2=1.08109894
 B3=1.08316835
 B4=1.78184159
 B5=1.17575297   (1.1604)
 A1=124.88341033
 A2=117.51712255
 A3=99.34623492
 A4=174.61875209
 D1=180.
 D2=0.
 D3=180.
 B1=1.67204007
 B2=1.08141145
 B3=1.08357648
 B4=1.78860298
 B5=1.17733864   (1.1606)
 A1=124.80092327
 A2=117.55695198
 A3=98.95303402
 A4=174.97920767
 D1=180.
 D2=0.
 D3=180.






















 



Table 3.  H2C=P-CN.  Rotational Constants (MHz).  Calc (1) = MP2/6-311+G(3df,3pd) and Calc (2) =  MP2/aug-cc-pVTZ optimization, each with approximate re(CN).







Calc (1)
Calc (2)
  Expt [1]






A 20155
19849
20127.0(16)

B   4088
  4083
  4067.758(11)

C   3399
  3386
  3377.722(11)


 








 









 






Table 4.  H2C=P-CN.  Dipole Moments and Quartic Centrifugal Distortion Constants.  Calc (1) = B3LYP/cc-pVTZ and Calc (2) = MP2/cc-pVTZ.











Calc (1)
Calc (2)

Expt [1]









a| /D

3.64

3.44



b| /D

0.30

0.25



 







Delta_J /kHz

1.58

1.64

1.53(21)

Delta_JK /kHz -
0.456
+
0.579
-
1.14(33)

Delta_K /kHz
241.

213.



delta_J /kHz
0.439

0.469



delta_K /kHz
15.8

16.4











DJ /kHz

1.42

1.47



DJK /kHz
0.478

1.62



DK /kHz
240.

212.



d1 /kHz -
0.439
-
0.469



d2 /kHz -
0.0778
-
0.0872












 









 








[1] M.C.Durrant, H.W.Kroto, and D.R.M.Walton, J.Mol.Spectrosc. 121,304(1987).


 








 









H2C=N-CN
H2C=P-Cl
H2P-CN




 









 









Table of Contents




Molecules/Nitrogen




 








 













CH2PCN.html






Last Modified 4 Feb 2014