Synthetic Metals 140 (2004) 113–115 Authors’ reply Answer to the comments on the paper: “Modulation of period of quantum beats from optical emissions from the excited electronic states of mercury triatomic clusters” [Synth. Met. 124 (2001) 267] E. Sarantopoulou a,∗ , C. Skordoulis b , A.C. Cefalas a , A. Vourdas c a National Hellenic Research Foundation, Athens 11635 Greece b Department of Physics, University of Ioannina, Ioannina, Greece c Department of Electrical Engineering and Electronics, University of Liverpool, Brownlow Hill, Liverpool L69 3GJ, UK Received 17 June 2003; received in revised form 21 October 2003; accepted 21 October 2003 The short article was intended to demonstrate that metal- lic clusters in excited electronic states of volcanic shape, in- dicate quantum bi-state functionality. Two different types of experimental configurations were used, time resolved/laser induced fluorescence and mass spectroscopy. In the first, the solar blind photomultiplier or the secondary electron multiplier were permanently connected to one of the two slits of the VUV monochromator under background pres- sure of 10 -6 mbar. It was used to detect laser and VUV scattered light at 157 nm (calibration, alignment) [1]. Op- tical signals in the visible part of the spectrum were de- tected with visible PMT tubes connected to the second slit of the VUV monochromator as in [2]. This consists the stan- dard VUV-Vis experimental configuration. The molecular beam apparatus maintained the background pressure inside the vacuum chamber as low as possible connected only with the mass spectroscopic experiments (... Besides the laser induced fluorescence techniques, mass spectroscopic tech- niques were employed as well in a modified configuration used for different type of experiments [4]). The assignment of the 485 nm (Hg 3 ∗ ) band [3], was sup- ported by time resolved and laser induced fluorescence spec- troscopy [2]. The time evolution of signals exhibited the structure of typical quantum beats. Coherent superposition was based on the splitting of the excited electronic state in a symmetric and an anti-symmetric one from the translation symmetry of the excited electronic states in the potential barrier [5]. It explains the experimental result that quantum beats were observed only for two or three vibronic levels near the top of the potential barrier as it is expected from theory [4]. Following the time scale of the events, Fig. 1, ∗ Corresponding author. Tel.: +30-210-7273839; fax: +30-210-7273842. E-mail address: esarant@eie.gr (E. Sarantopoulou). the initial laser pulse at 157nm was not involved in the co- herent superposition of the states, which was not affected by collisions at all. This is an intermolecular process and there was no phase change as the electron moves through the potential barrier when the transmission coefficient was equal to one. The time scale of the formation of the Hg 2 dimmer was determined by the pathways of the formation of the Hg metastable atoms, through dissociative explosion of the HgBr molecule [2] and it is independent from the number density of the molecules in the cell (Fig. 1). The time scale of the dissociative explosion was within pecosec- ond, and the instantaneous transfer of energy of 2.5 eV per HgBr molecule to the centre of mass of the photo-fragments implies that the Hg 2 /Hg 3 clusters were formed in the time scale within pecosecond. Furthermore, the time scale of the formation of the metastable Hg atoms through a different pathway following two photon absorption from the HgBr molecule at 157 nm, was verified from the detection of the corresponding Hg transitions at 404, 407, 312 nm. Under 193 nm excitation the formation of the Hg 2 /Hg 3 clusters is energetically unfavourable (Fig. 1), since the efficiency of formation of the Hg atoms is a process which depends on the wavelength of the laser (independent on laser intensity and background pressure conditions), and the position of the excited electronic states of the HgBr 2 molecule in the energy scale (Fig. 1). This eliminates the need for inten- sity dependent experiments (focusing on the laser beam), as in [6], where three photons were required to populate the Hg metastable states. The mass spectroscopic appara- tus consisted of a stainless steel chamber were the effusive molecular beam was placed. The HgBr 2 molecules were in- jected in a chamber through a 100 m orifice. The chamber was kept at the background pressure of ∼10 -6 mbar. The quantrupole mass spectrometer was placed in a different part of the chamber, at right angles to the effusive beam, and it 0379-6779/$ – see front matter © 2003 Elsevier B.V. All rights reserved. doi:10.1016/j.synthmet.2003.10.020