The Tool Desk
Outbyte PC Repair FREERepair Windows errors before they cause bigger problemsFix Now →Outbyte Driver Updater FREEScan for outdated or missing drivers - takes under a minuteDriver Scan →iTechGuides is reader-supported. When you buy through links on our site, we may earn an affiliate commission. As an Amazon Associate I earn from qualifying purchases. Learn more
A molecule made from two rubidium atoms can have a permanent electric dipole when the atoms occupy different electronic states. In the unusual ultracold Rydberg molecule reported in 2011, one atom is excited to a high-lying state and the other remains in its ground state. Their interaction distorts the Rydberg electron’s distribution, producing a body-fixed dipole of about 1 Debye. This refines the familiar symmetry rule; it does not make ordinary molecules of identical atoms polar.
Why identical atoms are usually expected to have no permanent dipole
A permanent electric dipole requires an uneven distribution of positive and negative charge. In the standard picture of a homonuclear diatomic molecule—one made from two atoms of the same element—the two ends are equivalent. Inversion symmetry therefore rules out a permanent dipole along the molecular axis.
That argument concerns the molecule’s symmetry, not just the names of its atoms. Two rubidium nuclei can be identical while the molecule’s prepared electronic state treats their surroundings differently. The 2011 result is an exceptional example of that distinction, not a general exception for all homonuclear molecules.
What made the rubidium Rydberg molecule different
The molecule was an ultralong-range Rydberg dimer: one rubidium atom was in its ground state, while the other had an electron excited to a high-lying Rydberg state. The ground-state atom sat within the spatial extent of the Rydberg electron’s wavefunction. In earlier work, scattering between that electron and the ground-state atom was shown to provide an attractive interaction that can bind the pair. Bendkowsky et al., Nature (2009)
#1 Best Overall
- Read Before You Buy — No Video Output: These adapters support charging and USB 2.0 data transfer, but cannot transmit video signals. Except for standard USB webcams (which use USB data only), they are not compatible with HDMI/DisplayPort cables, video-capable USB-C hubs, or docking stations with video output.
- Convert USB-A Ports to USB-C: Designed to connect USB-C earphones, cables, flash drives, card readers, and other USB-C accessories to standard USB-A ports. Plug-and-play with no drivers or software required.
- Aluminum Alloy Housing: Built with a sturdy aluminum alloy shell that aids in heat dissipation and protects against daily wear and scratches. Designed to maintain a stable and secure connection.
- Compact & Travel-Friendly: The ultra-compact design allows the adapter to stay plugged into your device without blocking adjacent ports or adding bulk, reducing wear and tear on your original USB ports.
- 12-Month Warranty: Backed by a 12-month manufacturer warranty for peace of mind. Designed to meet strict quality control standards for reliable everyday performance.
In the 2011 system, the interaction with the nearby ground-state atom mixed a nearly degenerate electronic manifold into the Rydberg state. That admixture shifted electron density toward the perturbing atom. The resulting electronic distribution was asymmetric even though both nuclei were rubidium. The observed linear Stark response—the molecule’s response to an applied electric field—provided evidence for a permanent dipole. Spectroscopy and detailed calculations supported the result. Li et al., Science (2011)
What the reported dipole means
Li and colleagues reported a dipole moment on the order of 1 Debye for this homonuclear Rydberg molecule. The figure describes the permanent dipole associated with the molecule-fixed electronic state; it does not mean the molecule necessarily points in one fixed direction in the laboratory when no field is applied. The experiment’s Stark response is how the dipole’s presence was identified. The 2011 paper
Rank #2
- 5-in-1 USB-C Hub: Experience comprehensive connectivity featuring a Power Delivery input, two USB-A 2.0 ports, a USB-A 3.0 port, and an HDMI port. (Note: The USB-C power delivery input port is only for connecting an external wall charger to power your laptop and cannot power peripheral devices.)
- 90W Pass-Through Charging: Achieve optimal charging with 90W pass-through power to your laptop, supported by a total input of 100W, with the hub reserving 10W for operational efficiency. (Note: Wall charger not included.)
- Quick Data Transfers: Accelerate your productivity with rapid data transfers using a high-speed 5Gbps USB 3.0 port and two 480Mbps USB 2.0 ports.
- 4K HDMI Display: Enhance your visual experience with a hub capable of delivering 4K resolution at 30Hz in both mirror and extend modes. Please note that this hub is compatible with MacBook (macOS 12 and newer), Windows 10 and 11, ChromeOS, and laptops equipped with DP Alt Mode and Power Delivery. Note: This device is not compatible with Linux.
- What You Get: Anker USB-C Hub (5-in-1, 4K HDMI), welcome guide, 18-month warranty, and our friendly customer service.
How this differs from a trilobite Rydberg molecule
“Trilobite” refers to a distinct kind of Rydberg molecular state, involving high-angular-momentum electronic character. A 2023 peer-reviewed report describes pure trilobite rubidium Rydberg molecules with dipoles in the kilo-Debye range and two vibrational series. Those much larger values belong to a different state regime; they are not revised measurements of the approximately 1-Debye molecule reported in 2011. Exploring the vibrational series of pure trilobite Rydberg molecules (2023)
Do these 3 things before closing this tab:
1Repair Windows errors before they cause bigger problems2Fix the driver behind crashes, sound loss and screen glitches3Clear out junk files and repair common Windows errors| Feature | 2011 homonuclear Rydberg molecule | 2023 pure trilobite Rydberg molecules |
|---|---|---|
| Electronic character | Low-angular-momentum Rydberg state with an admixture of a nearly degenerate manifold, as described by Li et al. (2011) Source | Pure trilobite states with high-angular-momentum character, as described in the 2023 study Source |
| Reported dipole scale | On the order of 1 Debye Source | Kilo-Debye range Source |
| Experimental context | Spectroscopy and a linear Stark response were used to identify the dipole; detailed calculations agreed with the observations Source | The study reports two vibrational series; the cited summary does not state a directly comparable Stark-measurement detail Source |
So, can a homonuclear molecule have a permanent dipole?
Yes, in a specially prepared electronic state such as this ultracold rubidium Rydberg molecule. The key is that identical nuclei do not force every possible electronic state to distribute charge symmetrically. Here, asymmetric excitation and the interaction with the second atom distort the electron density, creating a permanent body-fixed dipole without changing the atoms’ identity.
Quick Recap
Best Value
- 5-in-1 Connectivity: Equipped with a 4K HDMI port, a 5 Gbps USB-C data port, two 5 Gbps USB-A ports, and a USB C 100W PD-IN port. Note: The USB C 100W PD-IN port supports only charging and does not support data transfer devices such as headphones or speakers.
- Powerful Pass-Through Charging: Supports up to 85W pass-through charging so you can power up your laptop while you use the hub. Note: Pass-through charging requires a charger (not included). Note: To achieve full power for iPad, we recommend using a 45W wall charger.
- Transfer Files in Seconds: Move files to and from your laptop at speeds of up to 5 Gbps via the USB-C and USB-A data ports. Note: The USB C 5Gbps Data port does not support video output.
- HD Display: Connect to the HDMI port to stream or mirror content to an external monitor in resolutions of up to 4K@30Hz. Note: The USB-C ports do not support video output.
- What You Get: Anker 332 USB-C Hub (5-in-1), welcome guide, our worry-free 18-month warranty, and friendly customer service.
Rank #4
- Dual Converters, Infinite Potential：Includes 2× USB C male to USB A female adapters and 2× USB A male to USB C female adapters. Perfect for a wide range of uses—tablets with Bluetooth keyboards, expand USB ports on macbook, and more. Two different converters for all your daily needs
- Next-Level 10Gbps & 3A Charging: No more slow 480Mbps, this usb to usb c adapter has a transfer speed of up to 10Gbps, allowing you to do more transferring in less time. This usb adapter fits both USB A and USB C charger, supporting up to 3A fast charging
- Upgraded Exquisite Craftsmanship: With an aluminum alloy housing and metal connector, the usbc to usb adapter is extremely durable and sturdy. Rigorously tested to withstand more than 10,000 times of plugging and unplugging, ensuring long-lasting performance
- Broad Compatible: The usb c to usb adapter widely supports all USB C/ USB A devices like laptops, tablets, cellphones, car chargers, and phone chargers. Such as compatible with MacBook Pro/Air 2023/2022, Thunderbolt 4/3 Devices,Apple MagSafe Watch 9/8/7/SE/Ultra, iPad Pro 2022/2021, Samsung Galaxy S23/S20/S10, and iPhone 17/16/15 Pro. Plug and play
- Please Note: To reach 10Gbps speed, keep the cable under 3.3 ft. For USB A Male to USB C adapters, try flipping the USB C connector. USB C Male to USB A adapters support bidirectional 10Gbps transfer within 3.3 ft
Rank #3
- Sleek 7-in-1 USB-C Hub: Features an HDMI port, two USB-A 3.0 ports, and a USB-C data port, each providing 5Gbps transfer speeds. It also includes a USB-C PD input port for charging up to 100W and dual SD and TF card slots, all in a compact design.
- Flawless 4K@60Hz Video with HDMI: Delivers exceptional clarity and smoothness with its 4K@60Hz HDMI port, making it ideal for high-definition presentations and entertainment. (Note: Only the HDMI port supports video projection; the USB-C port is for data transfer only.)
- Double Up on Efficiency: The two USB-A 3.0 ports and a USB-C port support a fast 5Gbps data rate, significantly boosting your transfer speeds and improving productivity.
- Fast and Reliable 85W Charging: Offers high-capacity, speedy charging for laptops up to 85W, so you spend less time tethered to an outlet and more time being productive.
- What You Get: Anker USB-C Hub (7-in-1), welcome guide, 18-month warranty, and our friendly customer service.
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
