The perpendicular fundamental nu(5) of chloroform (CHCl3)-C-12-Cl-35: highresolution infrared study of the nu(5) band together with the millimetre-wave rotational spectrum

The infrared spectrum of the perpendicular fundamental nu(5) of chloroform around 776 cm(-1) has been studied by applying two high resolution methods. A short range from the central part of the spectrum was measured with a di ode laser by using a cold jet sample including chloroform in natural isotop ic abundancies. More than 100 rotational lines of (CHCl3)-C-12-Cl-35 could be assigned. The whole band region was measured by a Fourier transform spec trometer at a resolution of 0.0010 cm(-1). In this case an isotopically pur e sample of (CHCl3)-C-12-Cl-35 was used. Starting from the results of the d iode laser investigation more than 2000 lines could be assigned with J(max) = 91 and K-max = 58. In addition to the infrared spectra, millimetre-wave lines also were measured. A total of 58 lines corresponding to J values 22, 23 and 35 at the excited vibration state upsilon(5) = 1 were assigned and analysed. All the data from three different spectra were simultaneously fit ted and, for example, the results nu(0) = 775.961 50(3) cm(-1), B-5 - B-0 = -0.180 171(22) x 10(-3) cm(-1), C-5 - C-0 = -0.170 57(15) x 10(-3) cm(-1), and (C zeta)(5) = 0.047 5294(11) cm(-1) were obtained.