A cluster-transfer experiment 9 Be( 9 Be, 14 C * → α+ 10 Be)α was carried out using an incident beam energy of 45 MeV. This reaction channel has a large Q-value that favors populating the high-lying states in 14 C and separating various reaction channels. A number of resonant states are reconstructed from the forward emitting 10 Be + α fragments with respect to three sets of well discriminated final states in 10 Be, most of which agree with the previous observations. A state at 22.5(1) MeV in 14 C is found to decay predominantly into the states around 6 MeV in 10 Be daughter nucleus, in line with the unique property of the predicted band head of the σ-bond linear-chain molecular states. A new state at 23.5(1) MeV is identified which decays strongly into the first excited state of 10 Be.

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The spectra of the 133Cs 6P3/2–8S1/2 transition have been demonstrated by using both the double resonance optical pumping (DROP) and the optical–optical double resonance (OODR) techniques. Compared with the OODR technique, the DROP spectra show a much better signal-to-noise ratio and narrow spectral linewidth. When the frequency of a 795 nm external-cavity diode laser is stabilized to the DROP spectrum of 133Cs 6P3/2 F′ = 5–8S1/2 F″ = 4 transition, the lowest square root of the Allan variance of 4.1 × 10−12 at an averaging time of 100 s was obtained.

A cluster-transfer experiment of 9 Be( 9 Be, 14 C → α+ 10 Be)α at an incident energy of 45 MeV was carried out in order to investigate the molecular structure in high-lying resonant states in 14 C. This reaction is of extremely large Q-value, making it an excellent case to select the reaction mechanism and the final states in outgoing nuclei. The high-lying resonances in 14 C are reconstructed for three sets of well discriminated final states in 10 Be. The results confirm the previous decay measurements with clearly improved decay-channel selections and show also a new state at 23.5(1) MeV. The resonant states at 22.4(3) and 24.0(3) MeV decay primarily into the typical molecular states at about 6 MeV in 10 Be, indicating a well developed cluster structure in these high-lying states in 14 C. Further measurements of more states of this kind are suggested.

An inelastic excitation experiment was performed with a 12 Be beam at 29 MeV/u on a carbon target. New resonances close to the respective cluster separation thresholds were observed in 12 Be for the 4 He + 8 He and 6 He + 6 He decay channels, confirming the previously proposed molecular rotational bands. Using the model-independent angular correlation analysis, a 0 + spin parity is assigned to the remarkably large peak at 10.3 MeV in the 4 He + 8 He channel. A distorted wave Born approximation (DWBA) calculation was compared to the experimental differential cross section of this state, resulting in a largely enhanced monopole transition matrix element of 7.0 ± 1.0 fm 2 , in good agreement with the generalized two-center cluster model (GTCM) prediction assuming a preformed α-4n-α configuration. Together with the previously reported large cluster spectroscopic factor, the strong clustering in 12 Be is well demonstrated. The detection focused on the most forward angles, by using a zero-deg telescope, is essential in the present measurement.