R. L. Bhattacharjee

Submillimeter laser Stark spectroscopy of 14ND3

Abstract A submillimeter laser Stark spectrum of fully deuterated ammonia (14ND3) has been observed with the 195-μm and 195′-μm lines of the DCN laser. The spectra observed were identified as dipole forbidden a ← a and s ← s rotation-inversion transitions, the multiplet JK = 5K←4K in the ground vibrational state for K = 1, 2, 3, and 4. The forbidden zero-field rotation-inversion transition frequencies are given, and the K-dependent dipole-moment values are determined by virtue of the fact that the same transition could be observed at two different laser frequencies.

Stark spectroscopy of CD3OD with the HCN laser

Abstract The laser Stark spectrum of fully deuterated methanol has been studied using the 337 and 311-μm lines of the HCN laser. Numerous families of absorption lines have been observed for both parallel and perpendicular polarizations up to 60 kV/cm. An extensive series of absorption lines observed at 311 μm has been assigned to the J = 11 to 19 members of the K = 11 ← 10 E2 Q branch in the vt = 0 ground torsional state of CD3OD. An R-branch transition observed at 311 μm has been identified as the JK = 117 ← 106A, vt = 0 transition. Three families of resonances observed at λ = 337 μm are identified as JK = 183 ← 172E1, vt = 0; JK = 173 ← 164E1, vt = 1; and JK = 97 ← 86A, vt = 0, transitions. Zero-field frequencies for all the assigned transitions are given with improved accuracy over those calculated from available molecular constants. For the Q-branch series, the branch origin and the series expansion coefficients are presented.

Laser stark spectroscopy of CD3OH and13CH3OH at 311μm

Laser Stark spectra have been observed for CD3OH and13CH3OH using the 311 μm line of the HCN laser. The spectra were taken for both parallel and perpendicular polarizations up to 60,000 Volts/cm. For CD3OH, the two characteristic structures in the spectra have been identified as the JK=144←133, A± doublet in the vt=0 torsional state. For13CH3OH, the low field structure observed is assigned as JK=153←142, A− in the vt=0 torsional state.

Submillimeter laser Stark spectroscopy of13CH3F with the 337 μm line of the HCN laser

Submillimeter laser-Stark spectra have been observed for the isotopic species of methyl fluoride,13CH3F, using the 337 μm line of the HCN laser. We have identified the multiplet transitions as JK=18K←17K in the ground vibrational state. Ten distinct families with K=8, 9, 10, 11, 12, 13, 14, 15, 16 and 17 have been observed. Zero-field frequencies for all the transitions are given and in most cases with better accuracy than predicted from the previous constants.

Laser Stark spectroscopy of CD3Cl at λ=337μm

A submillimeter laser Stark spectrum has been observed for fully deuterated Methyl Chloride (CD3Cl) with the 337 μm line of the HCN laser up to Stark fields of about 54000 V/cm. The spectra were taken for both Parallel and Perpendicular Polarizations and the multiplet transitions were identified as JK=42K←41K in the ground vibrational state. Three families with K=12, 13 and 14 have been identified and their zero field frequencies have been given with improved accuracy over those calculated from available molecular constants.

Laser stark spectroscopy of SO2 with the HCN laser

The Far Infrared (FIR) laser Stark spectrum ofSO2 was investigated using the 337 μm line of the HCN laser. Two distinct families, one originating at low field and the other at high field, were observed. The high field transition is identified as theJK−1,K+1=225,17←214,18, v2=1 transition. A significant fourth-order Stark shift was observed for this transition in the presence of a large second-order Stark shift. The zero-field frequency of the assigned transition was obtained by accounting for the fourth-order contribution.