Ultralight vector dark matter search using data from the KAGRA O3GK run

Among the various candidates for dark matter (DM), ultralight vector DM can be probed by laser interferometric gravitational wave detectors through the measurement of oscillating length changes in the arm cavities. In this context, KAGRA has a unique feature due to differing compositions of its mirrors, enhancing the signal of vector DM in the length change in the auxiliary channels. Here we present the result of a search for U(1)B−L gauge boson DM using the KAGRA data from auxiliary length channels during the first joint observation run together with GEO600. By applying our search pipeline, which takes into account the stochastic nature of ultralight DM, upper bounds on the coupling strength between the U(1)B−L gauge boson and ordinary matter are obtained for a range of DM masses. While our constraints are less stringent than those derived from previous experiments, this study demonstrates the applicability of our method to the lower-mass vector DM search, which is made difficult in this measurement by the short observation time compared to the auto-correlation time scale of DM

HYDROGEN BOND MEDIATED VIBRONIC MODE MIXING AND ELECTRONIC ENERGY TRANSFER IN BENZOIC ACID DIMERS

Author Institution: Department of Chemistry, Indian Institute of Technology KanpurFluorescence excitation, hole burning and dispersed fluorescence spectra for SVL excitations of the pure and mixed dimers of benzoic acid and 3-fluorobenzoic acid are measured in a supersonic jet expansion. The spectral analysis reveals that the vibronic modes of benzoic acid are extensively mixed with the low-frequency intermolecular modes of the dihydrogen bonded interface, and the mixing is sensitive to the position of the fluorine substitution at the aromatic ring and overall symmetry of the conformers. In case of the mixed dimer, three electronic origin bands are identified corresponding to excitations of the benzoic acid and two conformers of 3-fluorobenzoic acid moieties, and the former is about 700 wavenumbers higher in energy that the latter two. Partial transfer of electronic energy is observed when the electronic origin of the benzoic acid moiety is excited state, and this occurs even there is no visible overlap between the emission spectrum of the donor and absorption spectra of the acceptor moieties. The spectra of different dimeric species will be presented and the role of hydrogen bonds in energy transfer process will be discussed

Hydrogen bond-induced vibronic mode mixing in benzoic acid dimer: a laser-induced fluorescence study

Laser-induced dispersed fluorescence spectra of benzoic acid dimer in the cold environment of supersonic jet expansion have been reinvestigated with improved spectral resolution of measurements. The spectra are analyzed with the aid of the normal mode vibrations of the dimer calculated by the ab initio quantum chemistry method at the DFT/B3LYP/6-311+G** level of theory. The analysis reveals that the low-frequency intermolecular hydrogen bond modes are mixed extensively with the carboxyl as well as aromatic ring vibrations upon electronic excitation. The mode mixing is manifested as the complete loss of mirror symmetry relation between the fluorescence excitation and dispersed fluorescence spectra of the S1 origin, and appearance of large number of cross-sequence transitions when the DF spectra are measured by exciting the low-energy vibrations near the S1 origin. The cross-sequence bands are found in all the cases to be the combinations of two nontotally symmetric fundamentals consisting of one of the intermolecular hydrogen bond modes and the other from the aromatic ring and carboxyl group vibrations. The implications of this mode mixing on the excited state dynamics of the dimer are discussed

Hydrogen bond mediated rotor-ring coupling in acetic acid-benzoic acid mixed dimer

In this work we demonstrate that a doubly hydrogen-bonded interface of two carboxylic acid groups behaves as efficient conduit to transmit the rotor effects for IVR acceleration in a phenyl ring. The phenomenon has been demonstrated by measuring the resolved emission spectra following SVL excitations in S1 of a 1:1 mixed dimer between acetic acid and benzoic acid. The role of the methyl rotor has been ascertained by comparing the results with those obtained for an analogous dimeric system between formic acid and benzoic acid

Conformational effects on vibronic spectra and excited state dynamics of 3-fluorobenzoic acid dimer

Two conformational isomers of 3-fluorobenzoic acid dimer (3-FBA2) have been identified in a supersonic jet expansion by use of laser-induced fluorescence excitation (FE), UV-UV hole-burning, and dispersed fluorescence (DF) spectroscopic methods. In the FE spectrum, the S1 origins of the two isomeric species appear at a frequency gap of only 24 cm-1, and the vibronic intensities of the redshifted dimer (dimer I) are about two times weaker than those of dimer II. However, ab initio quantum chemistry calculations at the MP2/6-31G** level of theory predict that all the isomeric species of 3-FBA2 have almost the same binding energy (∼17 kcal/mol) in the ground state. Furthermore, unlike benzoic acid dimer, the present system shows intense activity for a low-frequency mode in both the FE and DF spectra. With the aid of DFT (B3LYP/6-311G**) predicted normal mode frequencies, we have assigned the mode to the in-plane gear (cogwheel) vibration of the cyclic hydrogen-bonded frame of the dimer. The Franck-Condon profiles for vibronic excitation of the mode indicate that the distortion of the cyclic hydrogen bond frame as a result of S1←S0 excitation is larger for dimer I than dimer II. Moreover, the fluorescence lifetime at the S1 zero-point level of the former is also significantly smaller than the latter. Using the predictions of configuration interaction singles calculations, we have proposed that the spectral and dynamical differences between the two isomeric species observed in this study are manifestations of the different characteristics of their S1 surfaces. By measuring FE, DF, and hole-burning spectra of a mixed dimer between 3-fluobenzoic acid and benzoic acid we have shown that the isomeric features in the homodimer spectra are due to two locally excited rotamers of the 3-fluorobenzoic acid moiety

Structure and electronic spectroscopy of naphthalene-acenaphthene van der Waals dimer: hole-burning, dispersed fluorescence, and quantum chemistry calculations

Electronic spectroscopy of 1:1 van der Waals dimer of naphthalene and acenaphthene has been studied in a supersonic free jet expansion by measuring the laser-induced fluorescence excitation, dispersed fluorescence, and two-color hole-burning spectra. In fluorescence excitation spectrum the dimer exhibits a long progression of an intermolecular vibration, and similar vibronic structures are observed also in emission spectra from the origin region of the S<SUB>1</SUB> surface. The excimer formation from the locally excited state appears as a barrier crossing process and excess vibronic energy required to cross the barrier is about 420 cm<SUP>-1</SUP>. The equilibrium structure and binding energy of the dimer are computed by the ab initio quantum chemistry method at the MP2/6-31G and MP2/6-31+G*//MP2/6-31G levels. A parallel-displaced structure, in which two molecules are displaced from a fully overlapping geometry by 1.16 and 0.45 Å, respectively, along the long and short molecular axes, and maintains a vertical separation of 3.48 Å between two molecular planes, is found to be the most stable in the ground state. The BSSE corrected MP2/6-31+G*//MP2/6-31G binding energy of the dimer is 9.2 kcal/mol. The observed spectral and dynamical characteristics of the mixed dimer are compared to those reported for the naphthalene homodimer, and the differences are interpreted in terms of geometry and exciton resonance interactions

Vibrational coupling in carboxylic acid dimers

The vibrational level splitting in the ground electronic state of carboxylic acid dimers mediated by the doubly hydrogen-bonded networks are investigated using pure and mixed dimers of benzoic acid with formic acid as molecular prototypes. Within the 0–2000-cm-1 range, the frequencies for the fundamental and combination vibrations of the two dimers are experimentally measured by using dispersed fluorescence spectroscopy in a supersonic jet expansion. Density-functional-theory calculations predict that most of the dimer vibrations are essentially in-phase and out-of-phase combinations of the monomer modes, and many of such combinations show significantly large splitting in vibrational frequencies. The infrared spectrum of the jet-cooled benzoic acid dimer, reported recently by Bakker et al. [J. Chem. Phys.119, 11180 (2003)], has been used along with the dispersed fluorescence spectra to analyze the coupled g-u vibrational levels. Assignments of the dispersed fluorescence spectra of the mixed dimer are suggested by comparing the vibronic features with those in the homodimer spectrum and the predictions of density-functional-theory calculation. The fluorescence spectra measured by excitations of the low-lying single vibronic levels of the mixed dimer reveal that the hydrogen-bond vibrations are extensively mixed with the ring modes in the S1 surface

Identification of isomeric dimers of o-fluorobenzoic acid using laser-induced fluorescence spectroscopy

Three conformational isomers of o-fluorobenzoic acid dimer have been identified in a supersonic jet expansion by use of laser-induced fluorescence excitation and dispersed fluorescence spectroscopy. Using a mixed dimer of o-fluorobenzoic acid with benzoic acid, we have provided further evidence that the three isomers in the previous case originate due to two distinct internal rotational isomeric forms of each of the dimer moiety. Relative stability and geometries of all the dimers are computed by use of DFT theoretical method. The resolved fluorescence spectra of the three isomeric homodimers have been tentatively assigned by correlating the observed frequencies with the normal mode frequencies of the isomers predicted by DFT calculation