CH3CN, ν8
Methyl cyanide, acetonitrile, cyanomethane, ν8 band
Species tag 041511
Version1*
Date of EntryNov. 2016
ContributorH. S. P. Müller

Note: The entry is somewhat preliminary because of merging issues of lines and energies. For that matter, also no experimental lines have been merged yet.
The entry is based on data pertaining to the vibrational states v8 ≤ 2 and takes into account interactions between these states. Interactions with states v4 = 1, v7 = 1, and v8 = 3 were accounted for through spectroscopic parameters and appropriate interaction parameters. The fit was described in
(1) H. S. P. Müller, L. R. Brown, B. J. Drouin, J. C. Pearson, I. Kleiner, R. L. Sams, K. Sung, M. H. Ordu, and F. Lewen,
2015, J. Mol. Spectrosc. 312, 22
.
Vibrational ground state data with 14N hyperfine splitting were taken from
(2) S. G. Kukolich, D. J. Ruben, J. H. S. Wang, and J. R. Williams, 1973, J. Chem. Phys. 58, 3155;
from
(3) S. G. Kukolich, 1982, J. Chem. Phys. 76, 97;
and from
(4) D. Boucher, J. Burie, J. Demaison, A. Dubrulle, J. Legrand, and B. Segard, 1977, J. Mol. Spectrosc. 64, 290.
Additional, extensive data between 91 ans 790 GHz were taken from
(5) G. Cazzoli and C. Puzzarini, 2006, J. Mol. Spectrosc. 240, 153.
Two K = 14 transitions were taken from
(6) M. Šimecková, Š. Urban, U. Fuchs, F. Lewen, G. Winnewisser, I. Morino, K.M.T. Yamada, 2004, J. Mol. Spectrosc. 226, 123.
Further extensive data up to 1.63 THz were reported in (1) and in
(7) H. S. P. Müller, B. J. Drouin, and J. C. Pearson, 2009, Astron. Astrophys. 506, 1487.
The purely K-dependent terms were determined through ΔK = 3 infrared loops from
(8) R. Anttila, V.-M. Horneman, M. Koivusaari, and R. Paso, 1993, J. Mol. Spectrosc. 157, 198,
and from the interactions treated in (1).
The v8 = 1 data were mostly taken from (1). Additional millimeter wave data come from
(9) A. Bauer and S. Maes, 1969, J. Phys. (Paris) 30, 169.
The ν8 data were published by
(10) M. Koivusaari, V.-M. Horneman, and R. Anttila, 1992, J. Mol. Spectrosc. 152, 377.
The v8 = 2 data as well as the 2ν8 data were mostly taken from (1). Additional data come from
(11) A. Bauer and S. Maes, 1969, C. R. Acad. Sci. Ser. B 268, 1569,
and from
(12) R. Bocquet, G. Wlodarczak, A. Bauer, and J. Demaison, 1988, J. Mol. Spectrosc. 127, 382.
Parameters of three higher vibrational states were taken from
(13) A.-M. Tolonen, M. Koivusaari, J. Schroderus, S. Alanko, and R. Anttila, 1993, J. Mol. Spectrosc. 160, 554.
Vibrational identifiers in this and related entries are
0 for v = 0 (1 with HFS),
2 for v8 = 1, l = –1 (4 with HFS),
3 for v8 = 1, l = +1 (5 with HFS),
6 for v8 = 2, l = 0 (9 with HFS),
7 for v8 = 2, l = +2 (10 with HFS),
8 for v8 = 2, l = –2 (11 with HFS).
Transitions between vibrational states occur in the lower energy entry.
The rotational part of the partition function is complete up to 500 K (J up to 140 and K up to 30). Vibrational contributions have been considered in the calculation of the partition function for states up to about 1200 cm–1. Higher vibrational states contribute to less than 3.0 % at 300 K. Additional information on vibrational states is also available.
The transition dipole moment was determined in (1).

Lines Listed10358
Frequency / GHz<12358
Max. J81
log STR0-100.
log STR1-9.5
Isotope Corr.0.0
Egy / cm–1365.0244 / 0
 µa / D 
 µb / D0.43
 µc / D 
 A / MHz158010.6 / 158099.0
 B / MHz9226.419 / 9198.8992
 C / MHzB
 Q(500.0)52932.5986
 Q(400.0)30128.0215
 Q(300.0)15130.4545
 Q(250.0)10119.6538
 Q(225.0)8130.4079
 Q(180.0)5277.5726
 Q(150.0)3811.9477
 Q(120.0)2628.0493
 Q(75.00)1267.6705
 Q(37.50)449.0811
 Q(18.75)164.3168
 Q(9.375)64.0955
 Q(5.000)28.4924
 Q(2.725)13.8355
detected in ISM/CSMno


Database maintained by Holger S. P. Müller and Sven Thorwirth, programming by D. Roth and F. Schloeder