•We have recorded the LIF excitation spectra of YS in the 17 860–20 700 cm−1 region.•We also measured the DF spectra of YS in the 17 860–20 700 cm−1 region.•A new 2Σ+2Σ+ state, preserving charge-transfer nature, has been observed.•The FC factors calculation for the new bands has been performed.•The spin-rotation parameter γ(new2Σ+)γ(new2Σ+) has been determined to be 0.0206 cm−1.We have investigated the laser-induced fluorescence (LIF) excitation spectra and dispersed fluorescence (DF) spectra of yttrium monosulfide (YS) in the energy range of 17 860–20 700 cm−1. Rotational analyses indicated that almost all of the intense vibronic bands can be attributed to the new [19.38]2Σ+(υ′)-X2Σ+(υ″)[19.38]2Σ+(υ′)-X2Σ+(υ″) transition system. The missing (1, 2), (2, 1) and (3, 3) bands are caused by their very small Franck–Condon factors, as confirmed by our calculations. The new 2Σ+2Σ+ state has been suggested to arise from the electronic configuration of (core)1σ22σ21π33σ2π, featuring a charge-transfer nature. Moreover, the spin-rotation parameter γ   for the newly observed 2Σ+2Σ+ state has been determined to be 0.0206 cm−1, the magnitude of which is larger than the known γ(X2Σ+)γ(X2Σ+) (0.001427 cm−1) but smaller than γ(B2Σ+)γ(B2Σ+) (−0.1515 cm−1).

The NH(a1Δ) + CO(X1Σ+) product channel for the photodissociation of HNCO at 201 nm was investigated using the sliced velocity map ion imaging technique with the detection of NH(a1Δ) products via (2 + 1) resonance enhanced multiphoton ionization (REMPI). Images were measured for the NH(a1Δ) rotational states in the ground and vibrational excited states (v = 0 and 1). Correlation between the NH(a1Δ) and CO rovibrational state distributions were determined from these images. Experimental results show that the vibrational distribution of the CO fragment in the NH(a1Δ) + CO(X1Σ+) channel peaks at v = 1. The negative anisotropy parameter measured for the NH(a1Δ) (v = 0 and 1|j) products indicates a direct dissociation process for the N–C bond cleavage in the S1 state. A bimodal CO rotational distribution was observed, suggesting that HNCO dissociates in the S1 state in two distinctive pathways.

The even-parity autoionizing resonance series 4p5np′ [3/2]1,2, [1/2]1, and 4p5nf′ [5/2]3 of krytpon have been investigated by laser excitation from the two metastable states 4p55s [3/2]2 and 4p55s′ [1/2]0 in the photon energy region of 29000–40000 cm−1 at experimental bandwidth of ∼0.1 cm−1. The excitation spectra of the even-parity autoionizing resonance series, most of which are experimentally studied for the first time in this work, show typical asymmetric line shapes. Complementary information on level energies, quantum defects, line profile indices and resonance widths, resonance lifetimes and reduced widths of the autoionizing resonances are derived by Fano-type line-shape analyses of the experimental results. Results from this work indicate that the line profile index (q) and the resonance width (Γ) are approximately proportional to the effective principal quantum number (n*); the line separation of the 4p5np′ autoionizing resonances is also in good agreement with theoretical model.

The laser-induced fluorescence (LIF) spectrum of jet-cooled 48TiF has been obtained in the wavelength region of 245–270 nm for the first time. Six pairs of vibronic bands were observed and assigned to two new transitions [37.8]4Φ-X4Φ and 4Δ-X4Φ. Rotational analysis was carried out for the (ν′ = 0–3 to ν″ = 0) vibrational bands of the [37.8]4Φ3/2-X4Φ3/2 and [37.8]4Φ5/2-X4Φ5/2 subbands, and also, the (ν′, 0) and (ν′+1, 0) vibrational bands of the 4Δ1/2-X4Φ3/2 and 4Δ3/2-X4Φ5/2 subbands. The effective equilibrium molecular constants for the [37.8]4Φ3/2 and [37.8]4Φ3/2 upper states were determined. In addition, lifetime measurements were carried out for all of the observed bands under collision-free conditions. On the basis of the spectroscopic constants and lifetime measurements, the electronic transitions involved in the observed high-lying electronic states are discussed.

The laser-induced fluorescence excitation spectra of jet-cooled FeS molecules have been recorded in the energy range of 18 900–21 600 cm−1, in which four parallel and one perpendicular transitions were identified for the first time. Spectroscopic constants of the observed excited states of FeS were determined by analyzing their rotationally resolved spectra. In addition, the lifetimes of most observed bands were also measured.

The absorption spectra of jet-cooled AsH2 radicals were recorded in the wavelength range of 435–510 nm by cavity ringdown spectroscopy. The AsH2 radicals were produced by pulsed DC discharge in a molecular beam of a mixture of AsH3, SF6, and argon. Seven vibronic bands with fine rotational structures have been identified and assigned as the 000, 20n, and 21n (n = 1–3) bands of the A∼2A1–X∼2B1 electronic transition. Based on the previous studies of AsH2 radical, rotational assignments and rotational term values for each band were obtained, and the molecular parameters including vibrational constants, rotational constants, centrifugal distortion constants, and spin–rotation interaction constants were also determined.

Kr atoms were produced in their metastable states 4p55s [3/2]2 and 4p55s’ [1/2]0 in a pulsed DC discharge in a beam, and subsequently excited to the even-parity autoionizing Rydberg states 4p5np′ [3/2]1,2, [1/2]1 and 4p5nf′ [5/2]3 using single photon excitation. The excitation spectra of the even-parity autoionizing resonance series from the metastable Kr were obtained by recording the autoionized Kr+ ions with time-of-flight ion detection in the photon energy range of 29000–40000 cm−1. A wealth of autoionizing resonances were newly observed, from which more precise and more systematic spectroscopic data of the level energy and quantum defects were derived.

The laser-induced fluorescence (LIF) spectrum of jet-cooled CoF has been obtained in the wavelength region of 260–290 nm for the first time. Seventeen vibronic bands were observed and assigned to three types of transition from the ground state to upper states Ω′ = 3, 4, 5 by rotational analysis. A new vibrational transition with the 0–0 band at 34697.22 cm−1 has been assigned as the [34.7]3Γ5–X3Φ4 transition and effective equilibrium molecular constants for the upper state have been determined. In addition, lifetime measurements have been carried out for most of the bands under collision-free conditions. On the basis of the spectroscopic data and lifetime measurements, the electronic structures of these possible high-lying electronic states are discussed.

Resonance-enhanced multiphoton ionization (REMPI) spectra of N32S and N34S have been recorded in the range of 35700–40200 cm−1. The radical was generated by a pulsed dc discharge of a mixture of SF6 and N2 under a supersonic free jet condition. All the 16 observed bands of N32S radicals have been assigned, among which 12 bands belong to three transition progressions (v′=0−4, 0), (v′=1−4, 1) and (v′=2−4, 2) from the X2Π ground state to the B′2Σ+ upper state and the rest correspond to (9, 0), (10, 0), (11, 0) and (12, 0) bands of B2Π-X2Π transition, respectively. Analysis of the rotationally resolved spectra yields exhaustive spectroscopic constants of both the X2Π ground state and the B′2Σ+ excited state. The electronic transition bands of the isotopic molecule N34S have been rotationally analyzed for the first time and the rotational constants of the ground and upper states have been determined simultaneously.