CCL: Absolute shielding values of B2H6 or BF3:OEt2 at GIAO-Mp2/6-31+G*

 Sent to CCL by: "Mr  shabbir" [shabbir(-)]
 Hello CCL user,
 I am in a bit little confusion. I have calculated the 11B NMR spectra of a
 compound at GIAO-Mp2/6-31+G*. Now I want to correlate it with experimental.For
 this purpose I have to take reference compound as B2H6 or BF3:OEt2. I have tried
 my best to find their absolute shielding value and can get following important
 references as under
 The B NMR chemical shifts were first computed with B2H6 [calculated absolute
 shift, (sigma B) = 96.7] as a reference. The 11B NMR chemical shifts were
 finally referenced to BF3:OEt2 [deta (B2H6) 16.6 vs. BF3:OEt2].
 The 11B and 13C chemical shifts (6 values) are reported relative to the
 experimental standards, BF3OEt2 and tetramethylsilane (TMS), respectively.
 For 11B, where it is inconvenient to compute the experimental NMR standard, B2H6
 (which has delta 16.6 vs BF3eOEt2) is used instead. The sigma values for B2H6
 are as follows:
 GIAO-MP2/DZP =102.8 ppm and GIAO-MP2/TZP =100.7 ppm
 My question
 1-	On the basis of above lines, Can I take, 102.8 absolute shielding value of
 BF3OEt2 at GIAO-MP2/6-31+G*or (96.7+16.6)=113.3  .....?
 2-	Any one who knows any reference about the Absolute shielding values of B2H6
 or BF3:OEt2 at GIAO-Mp2/6-31+G* or higher?
 3-	Is there any scaling factor that can we use for NMR calctions?
 4-	Two signs are used in NMR shieldings, sigma or deta (lower cases of greek)
 difference b/w these two?
 thanks in advance