Rotational spectrum of 13C2-methyl formate (HCOO13CH3) and detection of the two 13C-methyl formate in Orion

Home

All issues

Volume 500 / No 3 (June IV 2009)

A&A, 500 3 (2009) 1109-1118

Full HTML

Free Access

Table 3:

Rotational constants in the principal axis system (PAM), angles between the principal axis and the methyl top axis and internal rotation parameters upon isotopic substitution.
	HCOOCH₃^a	HCOO¹³CH₃^b	H¹³COOCH₃^c	H¹³COOCH₃^d	H¹³COOCH₃^d	H¹³COOCH₃^d
	Global fit ( $v_{\rm t} = 0,1$ )	Global Fit ( $v_{\rm t} = 0$ )	Global Fit ( $v_{\rm t} = 0$ )	$v_{\rm t} = 0$	$v_{\rm t} = 1$	$v_{\rm t} = 2$
A(MHz)	19928.890(602)	19629.65(176)	19709.546(258)	19798.73249(43)	19917.3706(78)	20034.7(47)
B(MHz)	6952.169(585)	6804.42(171)	6909.555(225)	6864.74991(14)	6798.41624(91)	6748.99(76)
C(MHz)	5309.877(125)	5183.442(402)	5274.5475(189)	5262.53086(13)	5236.59430(30)	5213.360(21)
<(i,a)^e	52.97	51.68	52.48
$\theta_{\rm RAM}$ ^f	24.83	23.68	24.54	21.8604(79)	22.201(11)	22.867(34)
$\rho$	0.08427127(723)	0.0845207(106)	0.08407138(395)	0.084497(20)	0.086209(43)	0.08426(14)
F (cm^-1)	5.49038(129)	5.69168218^g	5.8039485^g	5.954(1)	5.7704(3)	5.802(1)
$\sigma$ ^h	1.43	1.08	0.67	0.86	0.99	1.07
N $^{\rm o}$ of transitions	4270	936	4954	4921	910	231

^a Rotation-torsion parameters for the normal species HCOOCH₃obtained in our work in the RAM-axis system, after transforming the RAM values for the A, B, C rotational parameters into PAM values following the procedure described in Carvajal et al. (2007). Note that Maeda et al. (2008a) also presents a fit for the normal species (but not including the same data set), using the ErHam procedure and fitting separately 5366 lines, 1228 lines and 213 lines belonging to $v_{\rm t} = 0$ , 1 and 2 with unitless standard deviations of 1.11, 1.18 and 0.81 respectively. Accuracy of their line measurements is about 100 kHz. ^b Rotation-torsion parameters for ¹³C₂-methyl formate from the present work transformed to the Principal Axis System. ^c Rotation-torsion parameters for ¹³C₁-methyl formate from the present work transformed to the Principal Axis System. The parameters were obtained with RAM model from a fit of all $v_{\rm t} = 0$ data presently available (4954 lines with 24 fitted parameters) in the literature and will be published soon. ^d Rotation-torsion parameters for ¹³C₁-methyl formate from Maeda et al. (2008b) obtained separately for each torsional state studied, using the ErHam procedure. ^e Angle in degrees between the a-principal axis and the methyl top axis (i). ^f The angle $\theta_{\rm RAM}$ between the a-principal axis and the a-RAM axis is given in degrees and obtained from Eq. (1) from Carvajal et al. (2007), with the parameters $A^{\rm RAM}$ , $B^{\rm RAM}$ , $C^{\rm RAM}$ , and $D_{\rm ab}$ of Table 2. ^g Fixed to the ab initio value. ^h Unitless standard deviation.

Source LaTeX | All tables | In the text

Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.

Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.

Initial download of the metrics may take a while.