Doublet Structure Research Articles

High resolution laser diode spectroscopy of the hot bands of C2HD in the first overtone region of C-H stretching

The frequencies of C2HD hot bands ro-vibrational lines of the first overtone of C-H stretching were measured using tunable diode lasers. To expand the measuring range to the region of the large rotational numbers, a heated gas cell was used. Measurements were made in the range R1–R36 and P2–P14 for the transition (2,0,0,1,0) ← (0,0,0,1,0), and in the range R1–R18 for the transition (2,0,0,0,1) ← (0,0,0,0,1). The rotational parameters of the upper and lower states for the band (2,0,0,1,0) ← (0,0,0,1,0) were determined. The doublet structure of ro-vibrational lines was studied. For the transition (2,0,0,1,0) ← (0,0,0,1,0), a sharp increase in the splitting value was detected at J > 25.

A Spectacular Devonian Trilobite Specimen, Dalmanites pratteni, From Illinois Helps Shed Light on How Trilobite Eyes Worked

In 1912, the Field Museum purchased Henry Pratten's collection of fossils. One of the specimens was a dalmanitid trilobite with large eyes (Fig. 1) that Pratten collected from the Devil’s Backbone. In 1933, this specimen was described as a new species of trilobite, Dalmanites pratteni (P 16704) (Roy 1933). Delo (1935) described a new genus of trilobite, Dalmanitoides and assigned it to a new family, Synphorinae. He noted Dalmanites pratteni has similar ornamentation to this genus. Delo (1940) later places D. pratteni in the genus Odontochile. Other authors refer to it as Dalmanites pratteni (Clarkson and Levi-Setti 1975;Levi-Setti 1975; Frankie et al. 2008). Holloway and De Carvalho (2009) refer to it as ‘Dalmanites’ pratteni and state that this species “probably belongs to the Synphoriinae”. The stratigraphic position of this specimen was not recorded. Seid et al. (2009) published a detailed geologic map of the Devil’s Backbone. Most of the ridge is Middle Devonian Grand Tower and St. Laurent formations. However, the southern end of the ridge is faulted, and the Lower Devonian Backbone Limestone and Crystal Creek Chert (Emsian) is exposed. Frankie et al. (2008) and Devera et al. (2020) report Dalmanites pratteni occurring from the Crystal Creek Chert, indicating that the original specimen may have been collected here. One of the most remarkable features of this fossil is the record number of lenses for a Phacopida. Roy (1933) reports 42 rows of eyes, however: “The exact number of lenses cannot be determined, as not all of them are preserved, nor are the areas which they occupied distinctly outlined. It is, however, certain that there are not less than 770 lenses on each eye.” (Roy 1933). I used images of the eyes and illustration software to estimate the number of lenses by filling in the geometric pattern they exhibit. I counted 730 lenses on the right eye and 712 lenses on left eye, which is missing a sizable piece (Fig. 2). The structure of some individual lenses in this specimen can be seen due to differential weathering. Clarkson and Levi-Setti (1975) reported the large round lenses were composed of a doublet structure that followed the principles established by Descartes (1637) and Huygens (1690) to eliminate spherical distortion. This doublet structure allowed the lens to gather more light and focus it on a single point, and strongly indicates that these trilobites had better vision then previously established (Clarkson and Levi-Setti 1975).

Pressure dependence of intermediate-range order and elastic properties of glassy Baltic amber.

Amber is a unique example of a fragile glass that has been extensively aged below its glass transition temperature, thus reaching a state that is not accessible under normal experimental conditions. We studied the medium-range order of Baltic amber by x-ray diffraction (XRD) at high pressures. The pressure dependences of the low-angle XRD intensity between 0 and 5 Å^{-1} were measured from 0 to 7.3 GPa by the energy-dispersive XRD. The first diffraction peak at 1.1 Å^{-1} and ambient pressure has a doublet structure consisting of the first sharp diffraction peak (FSDP) at 1.05 Å^{-1} and the second feature at 1.40 Å^{-1}. The peak position and the width of the FSDP increase as the pressure increases, while the intensity of the FSDP decreases. Below P_{0}=2.4 GPa, the rapid increase of the FSDP peak position was observed, while above P_{0}, the gradual increase was observed. Below P_{0}, voids and holes in a relatively low-density state are suppressed, whereas above P_{0}, the suppression becomes mild. Such a change suggests the crossover from the low- to high-density state at P_{0}. There is a close correlation between the pressure dependence of XRD and previously reported sound velocity results. The correlation between the mean-square fluctuation of the shear modulus on the nanometer scale and fragility in amber and other glass formers is also discussed.

Coupled unidirectional chaotic microwave graphs.

We experimentally investigate the undirected open microwave network Γ with internal absorption composed of two coupled directed halves, unidirectional networks Γ_{+} and Γ_{-}, corresponding to two possible directions of motion on their edges. The two-port scattering matrix of the network Γ is measured and the spectral statistics and the elastic enhancement factor of the network are evaluated. The comparison of the number of experimental resonances with the theoretical one predicted by the Weyl's law shows that within the experimental resolution the resonances are doubly degenerate. This conclusion was also corroborated by the numerical calculations. Though the network is characterized by the time-reversal symmetry, the missing level spectral statistics and the elastic enhancement factor are rather close to the Gaussian unitary ensemble predictions in random matrix theory. We used numerical calculations for the open nondissipative quantum graph possessing the same structure as the microwave network Γ to investigate the doublet structures in the spectrum which otherwise would not be experimentally resolved. We show that the doublet size distribution is close to the Poisson distribution.

AXDND1 is required to balance spermatogonial commitment and for sperm tail formation in mice and humans

Dynein complexes are large, multi-unit assemblies involved in many biological processes via their critical roles in protein transport and axoneme motility. Using next-generation sequencing of infertile men presenting with low or no sperm in their ejaculates, we identified damaging variants in the dynein-related gene AXDND1. We thus hypothesised that AXDND1 is a critical regulator of male fertility. To test this hypothesis, we produced a knockout mouse model. Axdnd1−/− males were sterile at all ages but presented with an evolving testis phenotype wherein they could undergo one round of histologically replete spermatogenesis followed by a rapid depletion of the seminiferous epithelium. Marker experiments identified a role for AXDND1 in maintaining the balance between differentiation-committed and self-renewing spermatogonial populations, resulting in disproportionate production of differentiating cells in the absence of AXDND1 and increased sperm production during initial spermatogenic waves. Moreover, long-term spermatogonial maintenance in the Axdnd1 knockout was compromised, ultimately leading to catastrophic germ cell loss, destruction of blood–testis barrier integrity and immune cell infiltration. In addition, sperm produced during the first wave of spermatogenesis were immotile due to abnormal axoneme structure, including the presence of ectopic vesicles and abnormalities in outer dense fibres and microtubule doublet structures. Sperm output was additionally compromised by a severe spermiation defect and abnormal sperm individualisation. Collectively these data identify AXDND1 as an atypical dynein complex-related protein with a role in protein/vesicle transport of relevance to spermatogonial function and sperm tail formation in mice and humans. This study underscores the importance of studying the consequences of gene loss-of-function on both the establishment and maintenance of male fertility.

High-resolution spectroscopy of LaAlO3-Pr3+ pseudo-cubic perovskite single crystals: Crystal-field parameters, hyperfine and deformation splittings

We report high-resolution measurements and analysis of the optical transmission and emission spectra of a concentration series of La(1-x)PrxAlO3 (x = 10−3, 9 ⋅ 10−3, and 2 ⋅ 10−2) single crystals in a wide frequency range ((2-27) ⋅ 103 cm−1) at temperatures 5–300 K, below the structural phase transition from the cubic Pm3‾m to the rhombohedral R3‾c phase. Pr3+ ions substitute for La3+ ions at sites with point symmetry D3. All recorded spectral lines are assigned to specific initial and final crystal-field (CF) energy levels, the scheme of CF levels is constructed and described by an appropriate set of CF parameters. The structural phase transition is accompanied by shear strains and the formation of ferroelastic twin domains of four types compressed along one of the four C3 axes in the parent cubic crystal lattice. Specific features of the measured spectra, namely, anomalous broadening of spectral lines and doublet structure of some lines corresponding to transitions between CF singlets and doublets, are considered as a result of interaction of 4f electrons with the field of random shear deformations competing at the boundaries of twin domains. Modeling of the observed line shapes was performed taking into account both hyperfine interactions and random lattice strains, as well as the effect of temperature. The width (6.6 ± 0.7)⋅10− 4 of the introduced two-dimensional distribution function of random strains was found from a comparison of simulated and measured profiles of the split spectral lines. The results of this work can be applied for quantitative assessment of crystal quality.

High-resolution investigation of the spin-rotation doublets of 14NO2 at 6.2 µm mid-infrared region using cavity ring-down spectroscopy

Nitrogen dioxide (14NO2) exhibits a unique doublet structure due to the presence of its unpaired electron, which results in a nonzero electronic angular momentum in the ground electronic state of the molecule. In this study, an investigation into high-resolution rovibrational spectral features associated with the spin-rotation doublets of 14NO2 was conducted using an external-cavity quantum cascade laser (EC-QCL)-coupled cavity ring-down spectrometer operating at 6.2 μm. Four spin-split doublets belonging to the RR branch of the (001)-(000) fundamental band were probed in the mid-IR spectral region. The air broadening and self-broadening coefficients were reported explicitly for each doublet component for the first time, to the best of our knowledge. The line-intensities were also quantified, and they were compared to the HITRAN database, revealing good agreement (<4% discrepancy).

Say Her Name: Remembering Anarcha, Betsey, and Lucy in Thinking About Algorithmic Finitude and Digital Sufficiency with Foucault and Laruelle

In The Order of Things, Michel Foucault first articulates what he calls the empirico-transcendental doublet, a circular logic according to which the subject, unlike other objects, can at once be an empirical object in experience and the transcendental conditions that make experience of the empirical possible. This doublet structure is tied, moreover, to what Foucault calls the analytic of finitude, a circinate pattern vacillating between a psychology of represented needs and an anthropology of the finitude of human life. Foucault’s argument is that it is this paradoxical structure which forms the historical a priori of knowledge in the modern episteme and, we may surmise, undergirds the enclosing logics of disciplinary societies. In time, Foucault’s contemporary, Gilles Deleuze, will describe the emergence of novel ambient and modulatory conditions that provoke a partial remaking of the boundaries of the subject into the dividual, or data-individual. This transformation, while unparalleled in some ways, relies on many extractive and surveilling methods and technologies developed in the previous episteme. Similarly, the somatechnical facialisation capabilities of digital technologies – described variously as digital epidermalisation, digital phrenology, and recursive redlining – are, I hold, prefigured by plantation logics. But while these are important historical contextualisations, the new algorithmic architectures we are embedded in have occasioned a veritable structural reorganisation of the circularity of the empirico-transcendental doublet. This new recursive epistemological arrangement – or algorithmic-transcendental doublet – causes dividuals to continually be assimilated into computerised temporalities that elicit financialised closed-loop epistemologies and grant the digital illegitimate authority over the radical immanence of life as lived. In addressing the interrelated theses presented here, I invoke François Laruelle’s project on non-standard philosophy to propose an alternative posture – one which refuses the violence of sufficiency: a knowledge that doubles the world via a transcendental synthesis by which the structure of possibility is precipitated always as a doublet.

Shpol’skii effect: new interpretation for the nature of the spectral multiplet structure and Bethe-splitting

New approach to the interpretation of the multiplet structure in the Shpol’skii spectra based on the symmetry consideration of the impurity molecule and crystal matrix is proposed. The reasons and peculiarities of doublet structure formation in the spectra of molecules without inversion center and highly symmetric molecules are considered. It is shown that the structure of electron density distribution in the naphthalene molecule causes a doubly degenerate of the electronic level of its ground state. The calculated data are compared with the experimental results. The main research stages and directions in the field of narrow-line spectroscopy of organic molecules are marked.

Luminescence spectrum of cadmium chalcogenide photovoltaic film structures and their power enhancement

A technology has been developed for producing photovoltaic film structures of CdTe, CdTe:In, CdTe/CdS by thermal vacuum deposition, which allows increasing their operating power. An analysis of their low- temperature photoluminescence spectra shows a significant increase in their spectral sensitivity. It has been experimentally shown that there is a clear correlation between the anomalous photovoltaic (APV) properties and the shape of the intrinsic photoluminescence band of obliquely deposited CdTe films. The photoluminescence spectrum of a polycrystalline CdTe film with APV property is qualitatively different from the spectra of a single crystal, large-block polycrystal and single microcrystal. The main contribution to the photoluminescence of the film comes from radiative recombination of free carriers (A-line with half-width ΔEA≈14.2±0.1 meV) and edge luminescence with a wide doublet structure (B- and C - lines with half- widths 18.5±0.1 meV and 32.2±0.1 meV). When doped with In impurities and as a result of heat treatment, the emission spectrum is greatly transformed in accordance with the change in the photoelectric properties of the film. In the photoluminescence spectrum of a CdTe layer in a CdTe/CdS heterostructure grown under identical technological conditions as a CdTe monolayer, an additional broad spectral line appears due to the presence of a heterointerface, the superhot region disappears, and the A-emission line narrows somewhat (ΔEA≈11.2±0.1 meV), which significantly differ the studied film structures from the known CdS/CdTe heterosystems of other authors. The proposed method for analyzing low-temperature photoluminescence spectra makes it possible to purposefully control the technology for manufacturing photovoltaic film structures. The results obtained are of interest for film optoelectronics and solar cell manufacturing.

The 5P3/2→6PJ(J=1/2,3/2) Electric Dipole Forbidden Transitions in Rubidium

This paper presents a general review of the results of the experimental and theoretical work carried out by our research group to study the 5P3/2→6PJ electric quadrupole transition in atomic rubidium. The experiments were carried out with room-temperature atoms in an absorption cell. A steady-state population of atoms in the 5P3/2 excited state is produced by a a narrow-bandwidth preparation laser locked to the D2 transition. A second CW laser is used to produce the forbidden transition with resolution of the 6PJ hyperfine states of both rubidium isotopes. The process is detected by recording the 420(422) nm fluorescence that occurs when the atoms in the 6PJ state decay directly into the 5S ground state. The fluorescence spectra show a strong dependence on the relative polarization directions of the preparation laser and the beam producing the forbidden transition. This dependence is directly related to a strong anisotropy in the populations of the 5P3/2 intermediate magnetic substates, and also to the electric quadrupole selection rules over magnetic quantum numbers. A calculation based on the rate equations that includes velocity and detuning dependent transition rates is adequate to reproduce these results. The forbidden transition is also shown to be an ideal probe to measure the Autler–Townes splitting generated in the preparation of the 5P3/2 state. Examples of spectra obtained with cold atoms in a magneto-optical trap (MOT) are also presented. These spectra show the expected Autler–Townes doublet structure with asymmetric line profiles that result as a consequence of the red-detuning of the trapping laser in the MOT.

Optical Trapping of a Polyatomic Molecule in an ℓ-Type Parity Doublet State.

We report optical trapping of a polyatomic molecule, calcium monohydroxide (CaOH). CaOH molecules from a magneto-optical trap are sub-Doppler laser cooled to 20(3) μK in free space and loaded into an optical dipole trap. We attain an in-trap molecule number density of 3(1)×10^{9} cm^{-3} at a temperature of 57(8) μK. Trapped CaOH molecules are optically pumped into an excited vibrational bending mode, whose ℓ-type parity doublet structure is a potential resource for a wide range of proposed quantum science applications with polyatomic molecules. We measure the spontaneous, radiative lifetime of this bending mode state to be ∼0.7 s.

Chiral Restoration of Nucleons in Neutron Star Matter: Studies Based on a Parity Doublet Model

We review the chiral variant and invariant components of nucleon masses and the consequence of their existence on the chiral restoration in extreme conditions, particularly in neutron star matter. We consider a model of linear realization of chiral symmetry with the nucleon parity doublet structure that permits the chiral invariant mass, m0, for positive and negative parity nucleons. The nuclear matter is constructed with the parity doublet nucleon model coupled to scalar fields σ, vector fields (ω,ρ), and mesons with strangeness through the U(1)A anomaly. In models with a large m0, the nucleon mass is insensitive to the medium, and the nuclear saturation properties can be reproduced without demanding strong couplings of the nucleons to the scalar fields σ and vector fields ω. We confront the resulting nuclear equations of state with nuclear constraints and neutron star observations and delineate the chiral invariant mass and effective interactions. To further examine the nuclear equations of state beyond the saturation density, we supplement quark models to set the boundary conditions from the high-density side. The quark models are constrained by the two-solar-mass conditions, and such constraints are transferred to nuclear models through the causality and thermodynamic stability conditions. We also calculate various condensates and the matter composition from nuclear to quark matter in a unified matter by constructing a generating functional that interpolates the nuclear and quark matter with external fields. Two types of chiral restoration are discussed: one due to the positive scalar charges of nucleons and the other triggered by the evolution of the Dirac sea. We found that the U(1)A anomaly softens equations of state from low to high density.

Strong configuration-interaction contributions to the angle-resolved 4p photoelectron spectra of atomic xenon

High-resolution photoelectron spectra of xenon (Xe) were measured in the $4p$ photoionization region. The anisotropy parameters \ensuremath{\beta} were obtained for several photoelectron peaks with angle-resolved photoelectron measurements. The various complicated spectral features were observed due to the perturbed $4{p}^{\ensuremath{-}1}$ spin-orbit doublet and adjacent satellite structures. An analysis based on a relativistic multiconfiguration calculation has been carried out. The key role of the strong interactions between the $4{p}^{\ensuremath{-}1}$ core hole and the $4{d}^{\ensuremath{-}2}nl$ configurations has been investigated in detail. Experimental peak energies and intensities are in good agreement with theory. We find that the many of the complicated features are $4{d}^{\ensuremath{-}2}nl$ satellite lines, and their intensities are determined mostly by the amount of $4{p}^{\ensuremath{-}1}$ configurations that are mixed in. The experimental \ensuremath{\beta} values agree quite well with theory, indicating that the photoelectron angular distributions are also strongly influenced by the $4p$ direct-ionization contributions.

Dielectric TM-Mode Y-Shaped Doublet Structure

This paper discusses dielectric TM-mode filters based on high permittivity Y-shaped ceramics. It is shown that this type of ceramic operates as a dual-mode resonator and therefore contributes two reflection zeros as well as one transmission zero (TZ) to the filter response. Hence, it can be interpreted as a doublet structure and used for the realization of quasi-elliptical filter responses of different order. The dual-mode resonator can be used in multiple different filter set-ups: On the one hand, a combination with classical TM <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$_{010}$</tex-math></inline-formula> -mode resonators is possible to allow the realization of TZs in an in-line filter configuration without using cross-coupling apertures. Therefore, negative or diagonal cross-couplings, which are often difficult to realize and handle, can be avoided. On the other hand, several Y-shaped ceramics can be coupled directly with each other to increase the number of TZs to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$n_{fz}=n/2$</tex-math></inline-formula> , where <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$n$</tex-math></inline-formula> is the order of the filter. Finally, it is shown that even a combination with extracted pole elements is realizable. Prototypes based on modular segments are manufactured as proof of concept.

Doublet structure in the optical spectrum of a semiconductor laser with optoelectronic feedback in a square-wave regime

We observe an optical spectrum consisting of a doublet in the output of a semiconductor laser diode with optoelectronic feedback in a dynamical regime in which a self-sustained square-wave modulation is observed, depending on injection current and feedback strength. The doublet frequency splitting is strongly correlated with the duty cycle of the square wave; both parameters as well as the relative magnitude of the peaks are observed to vary with the feedback level. A rate equation model reproduces the spectral doublets. The appearance of the doublet is attributed to active medium gain saturation and refractive index dependence on the carrier density.

Olefin coordination versus weak agostic C[sbnd]H[sbnd]M interactions in Sandwich-Type complexes of the split (3 + 2) Five-Electron donor hydrocarbon ligand Tricyclo[5.2.1.0]-deca-3,8-dien-5-yl (dicp) related to cyclopentadiene dimer

Sandwich-type complexes (dicp)MCp (M = Ti, V, Cr, Mn, Fe, Co, Ni; Cp = cyclopentadienyl) of the split (3 + 2) five-electron donor ligand tricyclo[5.2.1.0]-deca-3,8-dien-5-yl (dicp) related to cyclopentadiene dimer have been investigated by density functional theory. In the low-energy structures of the transition metal complexes (dicp)MCp (M = Ti, V, Cr, Mn, Fe), all of the split (3 + 2) five electrons from the dicp ligand are donated to the central transition metal atom leading to 14-, 15-, 16-, 17, and 18-electron configurations for the singlet (dicp)TiCp, quartet (dicp)VCp, triplet (dicp)CrCp, doublet (dicp)MnCp, and singlet (dicp)FeCp structures. For the late transition metals Co and Ni, only the allyl unit of the dicp ligand is strongly coordinated to the transition metal atom, in contrast to the Cp2Co and Cp2Ni in which all ten carbon atoms of the two cyclopentadienyl ligands are coordinated to the central metal atom. The potential energy surface for the manganese complex (dicp)MnCp is much more complicated than that of manganocene Cp2Mn, in which the doublet, quartet, and sextet structures are nearly degenerate in energy, with the quartet and sextet low-energy structures having only have part of the allyl or olefin unit coordinated to the central manganese atom. Weak agostic CHM interactions between the dicp ligand and the metal atoms, typically with M—H distances of ∼2.7 Å, are found in many of the (dicp)MCp complexes in contrast to the Cp2M (M = Ti, V, Cr, Mn, Fe, Co, Ni).

The specificity of photoluminescence n-CdS/p-CdTe in semiconductor heterostructures

The low-temperature (4.2 K) near-band-edge photoluminescence spectrum of a thin fine-grained (h, dcr≤1μm) polycrystalline CdTe layer in an n-CdS/p-CdTe film heterostructure subjected to frontal excitation by an Ar+ laser with an intensity of ~44 W/cm2 consists of a dominant intrinsic (e-h) emission band with a half-width ΔA=10-12 meV and a blue shift ΔEr » 25 meV of the red edge with respect to Eg, its LO+nLA phonon replica (ΔB»40 meV) with a weak doublet structure, and a wide (ΔD»100 meV) surface-interface luminescence band peaking at a frequency ħω»1.49 eV. Rear-side illumination of the photoresistive CdS layer in the intrinsic absorption range with an intensity Lill ≈ 5.102 lx almost completely destroys the e-hband and all related luminescence lines, which are replaced with an asymmetric polariton emission doublet having an exciton resonance frequency ħω»1.59 eV(Δex» 25 meV) and a wide line of shallow donor–acceptor pairs (ΔDAP»40 meV) at a frequency of ħω»1.54 eV, whose maximum intensity is almost two orders of magnitude lower than that of the A line in the absence of illumination.

Observation of Rabi dynamics with a short-wavelength free-electron laser

Rabi oscillations are periodic modulations of populations in two-level systems interacting with a time-varying field1. They are ubiquitous in physics with applications in different areas such as photonics2, nano-electronics3, electron microscopy4 and quantum information5. While the theory developed by Rabi was intended for fermions in gyrating magnetic fields, Autler and Townes realized that it could also be used to describe coherent light–matter interactions within the rotating-wave approximation6. Although intense nanometre-wavelength light sources have been available for more than a decade7–9, Rabi dynamics at such short wavelengths has not been directly observed. Here we show that femtosecond extreme-ultraviolet pulses from a seeded free-electron laser10 can drive Rabi dynamics between the ground state and an excited state in helium atoms. The measured photoelectron signal reveals an Autler–Townes doublet and an avoided crossing, phenomena that are both fundamental to coherent atom–field interactions11. Using an analytical model derived from perturbation theory on top of the Rabi model, we find that the ultrafast build-up of the doublet structure carries the signature of a quantum interference effect between resonant and non-resonant photoionization pathways. Given the recent availability of intense attosecond12 and few-femtosecond13 extreme-ultraviolet pulses, our results unfold opportunities to carry out ultrafast manipulation of coherent processes at short wavelengths using free-electron lasers.

Role of tensor interaction as salvation of cluster structure in Ti44

Background: The $^{44}$Ti nucleus has been known to have a $^{40}$Ca+$\alpha$ cluster structure, and inversion doublet structure has been observed; however, $\alpha$ cluster structure tends to be washed out when the breaking of the $\alpha$ cluster is allowed due to the spin-orbit interaction. Nevertheless, $\alpha$ clustering in medium-heavy nuclei is quite a hot subject recently. Purpose: The tensor interaction has been known to play an essential role in the strong binding of the $^4$He nucleus, which induces the two-particle-two-hole (2p2h) excitation. Since this excitation is blocked when another nucleus approaches, it is worthwhile to show whether the tensor effect works to keep the distance between $^4$He and $^{40}$Ca and becomes the salvation of the clustering in $^{44}$Ti. Methods: The spin-orbit effect is included in the cluster model by using the antisymmetrized quasi cluster model (AQCM) developed by the authors. We have also developed an improved version of the simplified method to include the tensor contribution ($i$SMT), which allows us to estimate the tensor effect within the cluster model. The competition of these two is investigated in the medium-heavy mass region for the first time. Results: According to AQCM, the spin-orbit interaction completely breaks the $\alpha$ cluster and restores the symmetry of $jj$-coupling shell model when the $\alpha$ cluster approaches the $^{40}$Ca core. On the other hand, $i$SMT gives a large distance between $\alpha$ and $^{40}$Ca due to the tensor effect. Conclusions: In $^{44}$Ti, because of the strong spin-orbit and tensor contributions, two completely different configurations ($jj$-coupling shell model and cluster states) almost degenerate, and their mixing becomes important.