\begin{table}%t6
\caption{\label{tab:CH3C15N} Lower state quantum numbers of rotational transitions 
of CH$_3$C$^{15}$N from present work, frequencies (MHz), uncertainties unc. (kHz), and 
residuals o$-$c (kHz) between observed frequencies and those calculated from 
the final set of spectroscopic parameters.}
\par
%\centerline

\small\begin{tabular}{crcrr | crcrr |  crcrr}
\hline \hline
$J''$ & \multicolumn{1}{c}{$K''$} & Frequency & \multicolumn{1}{c}{unc.} & o$-$c &
$J''$ & \multicolumn{1}{c}{$K''$} & Frequency & \multicolumn{1}{c}{unc.} & o$-$c &
$J''$ & \multicolumn{1}{c}{$K''$} & Frequency & \multicolumn{1}{c}{unc.} & o$-$c \\
\hline
 18 & 12 &  338023.606 &  10 &     0 & 35 & 11 &  640278.287 &  70 & $-$75 & 56 &  7 & 1013569.196 &  30 &    51 \\
 18 &  6 &  338710.019 &   8 &  $-$8 & 35 &  9 &  640754.725 &  30 &  $-$9 & 56 &  6 & 1013809.982 &  30 & $-$23 \\
 18 &  5 &  338780.216 &   3 &     1 & 35 &  7 &  641136.691 &  50 & $-$38 & 56 &  5 & 1014014.014 &  50 &    45 \\
 18 &  4 &  338837.680 &   3 &     1 & 35 &  6 &  641292.126 &  40 & $-$18 & 56 &  4 & 1014180.965 &  20 &     7 \\
 18 &  3 &  338882.394 &   3 &  $-$4 & 35 &  4 &  641531.486 &  30 & $-$18 & 56 &  3 & 1014310.943 &  50 &    36 \\
 18 &  2 &  338914.344 &   8 &  $-$8 & 35 &  3 &  641615.332 &  50 & $-$23 & 56 &  2 & 1014403.766 &  20 &     3 \\
 18 &  1 &  338933.536 &   5 &     6 & 35 &  2 &  641675.251 &  20 & $-$22 & 56 &  1 & 1014459.492 &  30 &  $-$0 \\
 18 &  0 &  338939.926 &   5 &     2 & 35 &  1 &  641711.248 &  20 &    16 & 56 &  0 & 1014478.090 &  50 &    19 \\
 24 & 12 &  444677.654 &  50 &    68 & 44 & 12 &  799556.798 & 100 & $-$10 & 57 &  8 & 1030975.149 &  50 &    27 \\
 24 & 11 &  444868.773 &  80 & $-$60 & 44 & 11 &  799895.712 &  80 & $-$58 & 57 &  6 & 1031502.077 &  20 &  $-$9 \\
 24 & 10 &  445043.705 &  50 &     5 & 44 &  9 &  800486.471 &  50 &  $-$2 & 57 &  5 & 1031709.364 &  30 &  $-$6 \\
 24 &  9 &  445202.122 &  50 &     2 & 44 &  8 &  800737.904 & 100 & $-$84 & 57 &  4 & 1031879.082 &  20 &     6 \\
 24 &  7 &  445469.416 &  50 &    36 & 44 &  7 &  800960.070 &  50 & $-$74 & 57 &  3 & 1032011.155 &  20 &    15 \\
 24 &  6 &  445578.097 &  50 & $-$19 & 44 &  6 &  801152.797 &  50 & $-$59 & 57 &  2 & 1032105.530
 &  20 &    23 \\
 24 &  5 &  445670.197 &  50 &     1 & 44 &  5 &  801315.982 &  50 & $-$66 & 57 &  1 & 1032162.147 &  20 &     4 \\
 24 &  4 &  445745.587 &  50 &     4 & 44 &  4 &  801449.656 &  50 &  $-$1 & 57 &  0 & 1032181.021 &  20 &  $-$4 \\
  24 &  3 &  445804.286 &  50 &    36 & 44 &  3 &  801553.593 &  50 & $-$37 & 60 &  8 & 1083996.412 &  30 & $-$21 \\
     24 &  2 &  445846.202 &  50 &    31 & 44 &  2 &  801627.891 &  50 & $-$35 & 60 &  7 & 1084292.050 &  50 & $-$17 \\
             24 &  1 &  445871.360 &  50 &    29 & 44 &  1 &  801672.512 &  50 &  $-$2 & 60 &  5 & 1084765.613 &  80 & $-$70 \\
              24 &  0 &  445879.744 &  50 &    26 & 44 &  0 &  801687.390 &  50 &    10 & 60 &  3 & 1085081.878 &  50 &    41 \\
                 25 & 11 &  462645.335 & 100 &    10 & 45 &  5 &  819063.889 &  50 & $-$13 & 60 &  1 & 1085240.023 &  20 & $-$15 \\
 25 & 10 &  462827.117 & 100 &    34 & 45 &  4 &  819200.272 &  50 & $-$71 & 60 &  0 & 1085259.811 &  20 &  $-$9 \\
  25 &  9 &  462991.739 &  50 &  $-$7 & 45 &  3 &  819306.491 &  50 & $-$29 & 61 & 10 & 1100941.061 &  50 &    29 \\
 25 &  8 &  463139.273 &  50 &    22 & 45 &  2 &  819382.243 &  80 &$-$148 & 61 &  9 & 1101320.232 &  50 & $-$73 \\
 25 &  7 &  463269.567 &  50 &    28 & 46 &  9 &  835943.102 & 150 & $-$54 & 61 &  6 & 1102220.449 &  20 &     8 \\
 25 &  6 &  463382.606 &  50 &    46 & 46 &  6 &  836637.725 &  80 & $-$26 & 61 &  5 & 1102440.856 &  30 & $-$18 \\
 \hline  
 25 &  5 &  463478.295 &  50 &    26 & 46 &  5 &  836807.842 &  80 & $-$10 & 61 &  3 & 1102761.793 &  20 &     8 \\
  25 &  4 &  463556.690 &  50 &    63 & 46 &  4 &  836947.184 &  80 &    67 & 61 &  2 & 1102862.131 &  20 &  $-$7 \\
 25 &  3 &  463617.624 &  50 &    18 & 46 &  3 &  837055.463 &  50 & $-$29 & 61 &  0 & 1102942.430 &  20 & $-$14 \\
 25 &  2 &  463661.238 &  50 &    58 & 46 &  2 &  837132.851 &  50 & $-$82 & 62 & 12 & 1117699.499 & 200 &   171 \\
 25 &  1 &  463687.317 &  50 & $-$13 & 46 &  1 &  837179.357 &  50 & $-$52 & 62 & 10 & 1118588.819 &  30 &     3 \\
 25 &  0 &  463696.065 &  50 &    17 & 49 & 12 &  888070.867 & 100 &     3 & 62 &  9 & 1118973.704 &  30 &    16 \\
 26 & 12 &  480213.412 & 100 &    51 & 49 & 11 &  888445.580 & 120 &    42 & 62 &  8 & 1119318.436 &  20 & $-$11 \\
 26 & 11 &  480419.811 & 100 &   143 & 49 & 10 &  888788.116 & 100 &  $-$1 & 62 &  7 & 1119622.944 &  20 & $-$18 \\
 26 &  9 &  480779.185 &  50 & $-$16 & 49 &  9 &  889098.523 &  50 &    52 & 62 &  6 & 1119887.123 &  20 &    11 \\
 26 &  8 &  480932.181 &  80 &$-$107 & 49 &  6 &  889835.075 &  50 &    23 & 62 &  5 & 1120110.797 &  20 &  $-$2 \\
 26 &  7 &  481067.510 &  50 &     2 & 49 &  5 &  890015.474 &  50 &    40 & 62 &  4 & 1120293.942 &  20 &     8 \\
 26 &  6 &  481184.797 &  50 &  $-$9 & 49 &  4 &  890163.134 &  50 &    17 & 62 &  3 & 1120436.478 &  30 &    32 \\
 26 &  5 &  481284.187 &  50 &    49 & 49 &  3 &  890278.046 &  50 &     5 & 63 & 11 & 1135800.408 & 120 &    63 \\
 26 &  4 &  481365.532 &  50 &    70 & 49 &  2 &  890360.170 &  50 &     7 & 63 &  8 & 1136971.561 &  30 &    17 \\
 26 &  3 &  481428.740 &  50 &  $-$8 & 49 &  1 &  890409.470 &  50 &    21 & 63 &  6 & 1137548.452 &  20 &     5 \\
 26 &  2 &  481473.947 &  50 & $-$23 & 49 &  0 &  890425.897 &  50 &    18 & 63 &  5 & 1137775.379 &  20 &     6 \\
 26 &  1 &  481501.168 &  50 &    56 & 50 & 11 &  906143.305 & 150 & $-$87 & 63 &  4 & 1137961.166 &  20 &     5 \\
 26 &  0 &  481510.165 &  50 &     6 & 50 & 10 &  906492.536 &  80 &    97 & 63 &  3 & 1138105.724 &  20 & $-$14 \\
 27 &  9 &  498564.375 &  50 & $-$25 & 50 &  9 &  906808.668 &  50 &    17 & 63 &  2 & 1138209.052 &  20 &     5 \\
 27 &  8 &  498723.057 & 100 &  $-$3 & 50 &  8 &  907091.879 &  80 & $-$30 & 63 &  1 & 1138271.082 &  30 &    32 \\
 27 &  7 &  498863.213 &  80 &    12 & 50 &  7 &  907342.068 &  80 & $-$35 & 64 & 11 & 1153431.417 &  80 &    18 \\
 27 &  6 &  498984.839 &  50 &    69 & 50 &  6 &  907559.150 &  50 &    15 & 64 & 10 & 1153868.550 &  50 &    26 \\
 27 &  5 &  499087.724 &  50 &     8 & 50 &  5 &  907742.947 &  50 &    25 & 64 &  8 & 1154619.250 &  30 &  $-$3 \\
 27 &  3 &  499237.616 &  50 &    24 & 50 &  4 &  907893.365 &  50 & $-$27 & 64 &  7 & 1154932.519 &  80 & $-$51 \\
 27 &  2 &  499284.459 &  50 &  $-$1 & 50 &  3 &  908010.479 &  50 &  $-$7 & 64 &  6 & 1155204.355 &  30 &  $-$4 \\
 27 &  0 &  499322.004 &  50 &    38 & 51 & 12 &  923448.206 & 100 & $-$16 & 64 &  5 & 1155434.482 &  30 & $-$29 \\
 28 &  9 &  516347.309 &  80 &    49 & 51 & 10 &  924192.510 & 100 &  $-$0 & 64 &  4 & 1155622.929 &  20 & $-$12 \\
 28 &  8 &  516511.508 &  50 &    27 & 51 &  9 &  924514.553 &  80 &  $-$9 & 64 &  3 & 1155769.523 &  80 & $-$50 \\
 28 &  7 &  516656.554 &  50 &    18 & 51 &  8 &  924803.059 &  50 &    10 & 64 &  2 & 1155874.320 &  80 & $-$32 \\
 28 &  6 &  516782.448 &  50 &    82 & 51 &  7 &  925057.871 &  50 &     9 & 64 &  1 & 1155937.201 &  30 & $-$34 \\
 28 &  5 &  516888.896 &  50 & $-$26 & 51 &  6 &  925278.880 &  50 & $-$21 & 64 &  0 & 1155958.150 &  30 & $-$49 \\
 28 &  3 &  517044.107 &  50 &    56 & 51 &  5 &  925466.075 &  50 &  $-$6 & 65 &  9 & 1171901.821 &  30 &    10 \\
 34 & 13 &  621972.452 &  50 & $-$23 & 51 &  4 &  925619.334 &  50 &     5 & 65 &  8 & 1172261.466 &  30 & $-$24 \\
 34 & 12 &  622261.132 &  50 &     8 & 51 &  3 &  925738.595 &  50 &    11 & 65 &  7 & 1172579.205 &  30 &    23 \\
 34 & 11 &  622527.126 &  30 &    33 & 51 &  2 &  925823.803 &  50 &     3 & 65 &  5 & 1173088.143 &  20 &    15 \\
 34 &  9 &  622990.550 &  50 & $-$45 & 51 &  1 &  925874.943 &  50 &     0 & 65 &  3 & 1173427.860 &  50 &  $-$7 \\
 34 &  8 &  623187.975 &  20 &    24 & 51 &  0 &  925891.997 &  50 &     4 & 65 &  2 & 1173534.097 &  20 & $-$11 \\
 34 &  6 &  623513.510 &  20 &    21 & 55 & 10 &  994948.576 & 150 & $-$48 & 65 &  0 & 1173619.153 &  20 &    28 \\
 34 &  5 &  623641.561 &  20 &    17 & 55 &  8 &  995602.961 &  80 & $-$85 & 66 & 12 & 1188185.703 & 150 &$-$111 \\
 34 &  4 &  623746.418 &  40 &    34 & 55 &  7 &  995876.199 &  50 &    26 & 66 &  9 & 1189533.633 &  80 &    73 \\
 34 &  3 &  623827.915 &  50 & $-$56 & 55 &  6 &  996113.103 &  50 &     6 & 66 &  7 & 1190220.192 &  30 & $-$24 \\
 34 &  2 &  623886.265 &  20 &  $-$4 & 55 &  5 &  996313.763 &  50 &    33 & 66 &  6 & 1190499.574 &  30 & $-$01 \\
 34 &  1 &  623921.231 &  30 & $-$27 & 55 &  3 &  996605.769 &  50 & $-$48 & 66 &  5 & 1190736.074 & 100 & $-$64 \\
 34 &  0 &  623932.881 &  30 & $-$41 & 55 &  2 &  996697.183 &  50 &    27 & 66 &  4 & 1190929.820 &  50 &     4 \\
 35 & 14 &  639388.490 & 150 &     4 & 55 &  1 &  996752.051 &  50 &    77 & 66 &  2 & 1191188.194 &  50 & $-$36 \\
 35 & 13 &  639708.307 & 100 & $-$38 & 55 &  0 &  996770.268 &  50 &    19 & 66 &  1 & 1191252.892 &  30 &    27 \\
 35 & 12 &  640004.964 &  40 & $-$44 & 56 &  9 & 1012977.101 &  30 & $-$21 &    &    &              &     &       \\
\hline  \end{tabular}
\end{table}