Magnetic Rotation Enhanced Velocity Modulation Research Articles

Rotational analysis of weak (4, 6) hot band in the comet-tail ( A2Π i– X2Σ +) system of the CO +

The ro-vibrational spectrum of the weak (4, 6) hot band in the comet-tail ( A 2Π i – X 2Σ +) system of CO + is observed by employing optical heterodyne and magnetic rotation enhanced velocity modulation spectroscopy. One hundred and twenty-four spectral lines are assigned to this band; thus, precise molecular constants of the levels involved are obtained from a weighted nonlinear least-squares fitting procedure combining with our previous spectrum of the (3, 6) band.

Rotational analysis of the (3, 6) band in the comet-tail ( A2Π i – X2Σ +) system of CO +

The direct observation and rotational analysis of the (3, 6) band in the comet-tail ( A 2Π i – X 2Σ +) system of CO + are carried out for the first time employing optical heterodyne and magnetic rotation enhanced velocity modulation spectroscopy. That 193 lines are assigned to this band ranging from 12 100 to 12 370 cm −1 results in most accurate molecular constants by nonlinear least-squares fitting procedure employing the effective Hamiltonians.

Study of (1, 4) band in the comet–tail ( A2Π i– X2Σ +) system of CO +

Ro-vibrational spectrum of the (1, 4) band in the comet–tail system of CO + cation is observed employing the optical heterodyne and magnetic rotation enhanced velocity modulation spectroscopy in the range of 13 189–13 472 cm −1. Two hundred and eighteen spectral lines are assigned to 12 branches of this band for the first time, thus, precise molecular constants of the levels involved are obtained by nonlinear least-squares fitting procedure combining with our previous spectrum of the (1, 2) band.

New rovibrational analysis of A–X absorption spectrum of [formula omitted

Two bands of the A 2Π u – X 2Π g spectrum of 35 Cl 2 + and one band of 35Cl 37Cl + in the region between 16 820 and 17 350 cm −1 have been recorded using optical heterodyne magnetic rotation enhanced velocity modulation spectroscopy. It is the first time to report the rotational analyses of these bands. The little magnetic enhancement of these lines confirms the identity of these bands as due to the Ω = 1/2 component of the electronic transition in spite of the paramagnetic feature of Cl 2 + molecule.

Rotational analysis of (6, 20), (4, 20), and (2, 18) bands in the second negative ( A2Π u– X2Π g) system of [formula omitted] cation

The second negative ( A 2Π u – X 2Π g ) system of O 2 + were investigated in the 12100–14100 cm −1 near infrared region at high resolution by employing optical heterodyne magnetic rotation enhanced velocity modulation technique. Three new hot bands (2, 18), (4, 40) and (6, 20) were observed for the first time. From the rotational analysis of the line positions, precise molecular constants of the states involved were determined with an accuracy of 0.0028 cm −1.

Rovibration spectrum study of three hot bands with ν′′ ⩾ 18 in the second negative system ( [formula omitted]– [formula omitted]) of 16O 2+ ion

The second negative ( A 2 Π u – X 2 Π g ) system of O 2 + was studied in the near infrared region at high resolution using a Ti–sapphire laser system. Optical heterodyne magnetic rotation enhanced velocity modulation technique was employed to record rich absorption spectrum, three new hot bands (3, 18), (4, 19), and (3, 19) were observed and rotationally analyzed for the first time by a nonlinear least-square fitting procedure using a standard Hamiltonian, thus, precise molecular constants of the states involved were obtained.

The absorption spectra of H2O+ and D2O+ in the visible and near infrared region

The absorption spectra of the electronic transition of H2O+ and D2O+ are investigated in the visible region from 16 400 to 17 600 cm−1 and in the near infrared region from 12 200 to 14 000 cm−1 using optical heterodyne magnetic rotation enhanced velocity modulation spectroscopy (OH-MR-VMS). Three subbands including 111 spectral lines of H2O+ and seven subbands including 209 spectral lines of D2O+ are observed and analysed, among which four subbands, Σ (0,9,0)−(0,0,0), Δ (0,9,0)–(0,0,0), Π (0,8,0)–(0,0,0) and Π (0,10,0)–(0,0,0) of D2O+ in the near infrared region are studied for the first time. Holding the molecular constants of the lower state fixed at the published values, a set of molecular constants and rotational energy terms for each observed vibronic level of the upper state are obtained.

Study of hot bands in the B 2 + u - X 2 + g system of C - 2 anion

Optical heterodyne magnetic rotation enhanced velocity modulation spectroscopy was employed to observe the visible absorption spectra of the B2Σ+u-X2Σ+g electronic transition of C-2. Four hot bands (0,1), (1,2), (2,3) and (3,4) have been observed and the band (3,4) is measured directly for the first time, so far as we know, by absorption. A rotational analysis was carried out to obtain molecular constants. With the Franck-Condon principle and the vibrational Boltzmann distribution, we have estimated the vibrational temperature of C-2 to be about 3000K.

Observation and analysis of two subbands in the [formula omitted] absorption spectrum of H 2O +

The absorption spectrum of the A ̃ 2A 1– X ̃ 2B 1 electronic transition of H 2O + has been observed in the visible region between 16 600–17 600 cm −1 using optical heterodyne magnetic rotation enhanced velocity modulation spectroscopy. Altogether 100 lines were assigned to the Σ(0,11,0)–(0,0,0) and Δ(0,11,0)–(0,0,0) subbands, and precise molecular constants for the two vibronic levels of the A ̃ 2A 1 electronic state were obtained with the molecular constants of the ground state held fixed at literature values.

Measurement of the absorption spectrum of H2O+ in the visible region

Together with the 74 lines belonging to (0,9,0)-(0,0,0) band, the high-resolution absorption spectrum of H2O+ A2A1 - X2B1 system was observed in the visible region of 16680–17300 cm−1 using optical heterodyne magnetic rotation enhanced velocity modulation spectroscopy for the first time, which verifies the high sensitivity and high signal to noise ratio (S/N) of this technique.

Study on the (1, 2) and (2, 3) bands in the comet-tail system of 12C16O+ by optical heterodyne magnetic rotation enhanced velocity modulation spectroscopy

Optical heterodyne magnetic rotation enhanced velocity modulation spectroscopy was employed to observe the absorption spectra of the (1, 2) and (2, 3) bands of the comet-tail (A2 Πi—X2Σ+) system of CO+ in the visible region. A rotational analysis was performed to obtain more precise molecular constants for the four involved vibrational levels. Moreover, accurate RKR potentials and the Franck-Condon factors are given for these four vibronic levels. This calclulation reveals that v = 0, 5, 10 vibrational levels in the A state will be perturbed by the v = 10, 14, 18 levels in the × state, respectively, and the v = 9 level might be weakly perturbed by the v = 17 level.

Reinvestigation of the A2Πu–X2Σg+ (11, 5) and (12, 6) Bands of N2+ by Optical Heterodyne Magnetic Rotation Enhanced Velocity Modulation Spectroscopy

Reinvestigation of the A2Πu–X2Σg+ (11, 5) and (12, 6) Bands of N2+ by Optical Heterodyne Magnetic Rotation Enhanced Velocity Modulation Spectroscopy