Rotational spectroscopic study of hydrogen cyanide embedded in small 4He clusters

Abstract

High resolution microwave spectra of the a-type, J = 1-0, transitions of He(N = 1-6)-H(12)C(14)N, He(N = 1-6)-H(13)C(14)N, He(N = 1-6)-H(12)C(15)N, He(N = 1-7)-D(12)C(14)N, and He(N = 1-6)-D(13)C(14)N clusters produced in a supersonic jet expansion were measured and analyzed. The resulting effective rotational constants, B(eff), initially decrease with the number of the attached helium atoms before reaching a minimum at N = 3 helium atoms for all isotopologues. The subsequent increase in B(eff) for N ≥ 4 is indicative of the onset of microscopic superfluidity. Comparison of our experimental B(eff) constants with those from quantum Monte Carlo simulations [A. A. Mikosz, J. A. Ramilowski, and D. Farrelly, J. Chem. Phys. 125, 014312 (2006)] reveals a nearly congruent trend in B(eff) for N up to 6. Analysis of the hyperfine structure of the (14)N containing isotopologues yielded a gradual incremental increase in the magnitude of χ(aa) and <P(2)(cos θ)> for N = 1-6, which suggests the internal rotation of the HCN molecule is becoming increasingly hindered.

Direct Spectroscopic Detection of the Orientation of Free OH Groups in Methyl Lactate–(Water)1,2 Clusters: Hydration of a Chiral Hydroxy Ester

“…[17] Experimental details and an example broadband spectrum are provided in the Supporting Information and Figure S1. The final frequency measurements were performed with a cavity based FTMW spectrometer.…”

Chirped‐Pulse and Cavity‐Based Fourier Transform Microwave Spectra of the Methyl Lactate⋅⋅⋅Ammonia Adduct

“…[14,15] The spectral search for the binary adduct was carried out using a broadband chirped-pulse Fourier transform microwave (FTMW) spectrometer. [16] Broadband spectra of three different samples, namely ML, NH 3 , and ML + NH 3 , all in neon, were measured in the 7.7-10.4 GHz region using 10 6 averaging cycles. Transitions that require the presence of both ML and NH 3 could be readily identified.…”

Chirped‐Pulse and Cavity‐Based Fourier Transform Microwave Spectra of the Methyl Lactate⋅⋅⋅Ammonia Adduct

“…The survey scans were carried out using a newly constructed chirped-pulse FTMW spectrometer [16] based on designs reported previously. ML (99 %, Sigma Aldrich), 14 NH 3 (98 %, Scott Speciality Gases Inc.), 15 NH 3 (98 %, Cambridge Isotope Laboratories Inc.), and neon (99.9990 %) were used without further purification.…”

“…Only one chiral molecule-NH 3 adduct, namely glycidol···NH 3 , was studied before using high-resolution spectroscopy. [16] Broadband spectra of three different samples, namely ML, NH 3 , and ML + NH 3 , all in neon, were measured in the 7.7-10.4 GHz region using 10 6 averaging cycles. [11][12][13] In this work, we report a detailed rotational spectroscopic study of the ML···NH 3 adduct, in combination with high-level ab initio calculations.…”